Merge branch 'dev' into device-verification

# Conflicts:
#	autotests/testfilecrypto.cpp
#	lib/connection.cpp
#	lib/connection.h
#	lib/database.cpp
#	lib/database.h
#	lib/e2ee/qolmoutboundsession.cpp
#	lib/e2ee/qolmoutboundsession.h
#	lib/eventitem.h
#	lib/events/encryptedevent.cpp
#	lib/events/encryptedevent.h
#	lib/events/encryptedfile.cpp
#	lib/events/encryptedfile.h
#	lib/events/keyverificationevent.cpp
#	lib/events/keyverificationevent.h
#	lib/events/roomkeyevent.h
#	lib/room.cpp
#	lib/room.h

191 files changed, 4944 insertions, 3651 deletions

diff --git a/.clang-format b/.clang-format
index 8375204a..70864160 100644
--- a/.clang-format
+++ b/.clang-format
@@ -14,23 +14,26 @@
 # to borrow from the WebKit style. The values for such settings try to but
 # are not guaranteed to coincide with the latest version of the WebKit style.
 
+# This file assumes ClangFormat 12 or newer
+
 ---
 Language: Cpp
 BasedOnStyle: WebKit
 #AccessModifierOffset: -4
 AlignAfterOpenBracket: Align
-#AlignConsecutiveMacros: false
-#AlignConsecutiveAssignments: false
-#AlignConsecutiveDeclarations: false
+#AlignArrayOfStructures: None # ClangFormat 13
+#AlignConsecutiveMacros: None
+#AlignConsecutiveAssignments: None
+#AlignConsecutiveDeclarations: None
 AlignEscapedNewlines: Left
-AlignOperands: true # 'Align' since ClangFormat 11 
+AlignOperands: Align
 #AlignTrailingComments: false
 #AllowAllArgumentsOnNextLine: true
-#AllowAllConstructorInitializersOnNextLine: true
+AllowAllConstructorInitializersOnNextLine: true
 #AllowAllParametersOfDeclarationOnNextLine: true
 #AllowShortEnumsOnASingleLine: true
 #AllowShortBlocksOnASingleLine: Empty
-#AllowShortCaseLabelsOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: true
 #AllowShortFunctionsOnASingleLine: All
 #AllowShortLambdasOnASingleLine: All
 #AllowShortIfStatementsOnASingleLine: Never
@@ -39,41 +42,49 @@ AlignOperands: true # 'Align' since ClangFormat 11
 #AlwaysBreakAfterReturnType: None
 #AlwaysBreakBeforeMultilineStrings: false
 AlwaysBreakTemplateDeclarations: Yes
+#AttributeMacros:
+#  - __capability
 #BinPackArguments: true
 #BinPackParameters: true
 BraceWrapping:
-  AfterCaseLabel:  false
-  AfterClass:      false
-  AfterControlStatement: Never # Switch to MultiLine, once https://bugs.llvm.org/show_bug.cgi?id=47936 is fixed
-  AfterEnum:       false
+#  AfterCaseLabel:  false
+#  AfterClass:      false
+  AfterControlStatement: Never # Switch to MultiLine with ClangFormat 14 (https://bugs.llvm.org/show_bug.cgi?id=47936)
+#  AfterEnum:       false
   AfterFunction:   true
-  AfterNamespace:  false
-  AfterStruct:     false
-  AfterUnion:      false
-  AfterExternBlock: false
-  BeforeCatch:     false
-  BeforeElse:      false
-  IndentBraces:    false
+#  AfterNamespace:  false
+#  AfterStruct:     false
+#  AfterUnion:      false
+#  AfterExternBlock: false
+#  BeforeCatch:     false
+#  BeforeElse:      false
+#  BeforeLambdaBody: false # Blows up lambdas vertically, even if they become _very_ readable
+#  BeforeWhile:     false
+#  IndentBraces:    false
   SplitEmptyFunction: false
   SplitEmptyRecord: false
   SplitEmptyNamespace: false
 BreakBeforeBinaryOperators: NonAssignment
+#BreakBeforeConceptDeclarations: true
 BreakBeforeBraces: Custom
-#BreakBeforeInheritanceComma: false
+#BreakBeforeInheritanceComma: false # deprecated?
 #BreakInheritanceList: BeforeColon
 #BreakBeforeTernaryOperators: true
 #BreakConstructorInitializersBeforeComma: false # deprecated?
 #BreakConstructorInitializers: BeforeComma
 #BreakStringLiterals: true
 ColumnLimit: 80
+#QualifierAlignment: Leave # ClangFormat 14?
 #CompactNamespaces: false
-#ConstructorInitializerAllOnOneLineOrOnePerLine: false
+ConstructorInitializerAllOnOneLineOrOnePerLine: true
 #ConstructorInitializerIndentWidth: 4
 #ContinuationIndentWidth: 4
-Cpp11BracedListStyle: false
+#Cpp11BracedListStyle: true
 #DeriveLineEnding: true
 #DerivePointerAlignment: false
-FixNamespaceComments: true
+#EmptyLineAfterAccessModifier: Never # ClangFormat 14
+EmptyLineBeforeAccessModifier: LogicalBlock
+#FixNamespaceComments: false # See ShortNamespaces below
 IncludeBlocks: Regroup
 IncludeCategories:
   - Regex:    '^<Qt.+/'
@@ -88,12 +99,17 @@ IncludeCategories:
     Priority: 1
 IncludeIsMainRegex: '(_test)?$'
 #IncludeIsMainSourceRegex: ''
+#IndentAccessModifiers: false # ClangFormat 13
 #IndentCaseLabels: false
+#IndentCaseBlocks: false
 IndentGotoLabels: false
 IndentPPDirectives: AfterHash
+#IndentExternBlock: AfterExternBlock
+IndentRequires: true
 #IndentWidth: 4
 #IndentWrappedFunctionNames: false
 KeepEmptyLinesAtTheStartOfBlocks: false
+#LambdaBodyIndentation: Signature # ClangFormat 13
 #MacroBlockBegin: ''
 #MacroBlockEnd:   ''
 #MaxEmptyLinesToKeep: 1
@@ -102,34 +118,56 @@ PenaltyBreakAssignment: 10
 PenaltyBreakBeforeFirstCallParameter: 70
 PenaltyBreakComment: 45
 #PenaltyBreakFirstLessLess: 120
+#PenaltyBreakOpenParenthesis: 0 # ClangFormat 14
 PenaltyBreakString: 200
 #PenaltyBreakTemplateDeclaration: 10
 PenaltyExcessCharacter: 40
-PenaltyReturnTypeOnItsOwnLine: 150
+PenaltyReturnTypeOnItsOwnLine: 200
+#PenaltyIndentedWhitespace: 0
 #PointerAlignment: Left
+#PPIndentWidth: -1
+#ReferenceAlignment: Pointer # ClangFormat 13
 #ReflowComments: true
+#ShortNamespaceLines: 1 # ClangFormat 13 - to use with FixNamespaceComments
 #SortIncludes: true
 #SortUsingDeclarations: true
 #SpaceAfterCStyleCast: false
 #SpaceAfterLogicalNot: false
 #SpaceAfterTemplateKeyword: true
 #SpaceBeforeAssignmentOperators: true
-#SpaceBeforeCpp11BracedList: true
+#SpaceBeforeCaseColon: false
+SpaceBeforeCpp11BracedList: false
 #SpaceBeforeCtorInitializerColon: true
 #SpaceBeforeInheritanceColon: true
 #SpaceBeforeParens: ControlStatements
+#SpaceBeforeParensOptions: # ClangFormat 14
+#  AfterControlStatements: true
+#  AfterForeachMacros: true
+#  AfterFunctionDefinitionName: false
+#  AfterFunctionDeclarationName: false
+#  AfterIfMacros:   true
+#  AfterOverloadedOperator: false
+#  BeforeNonEmptyParentheses: false
+SpaceAroundPointerQualifiers: After
 #SpaceBeforeRangeBasedForLoopColon: true
 SpaceInEmptyBlock: false
 #SpaceInEmptyParentheses: false
 #SpacesBeforeTrailingComments: 1
-#SpacesInAngles:  false
+#SpacesInAngles: false # 'Never' since ClangFormat 13
 #SpacesInConditionalStatement: false
-#SpacesInContainerLiterals: true
+SpacesInContainerLiterals: false
 #SpacesInCStyleCastParentheses: false
+#SpacesInLineCommentPrefix: # ClangFormat 13
+#  Minimum:         1
+#  Maximum:         -1
 #SpacesInParentheses: false
 #SpacesInSquareBrackets: false
 #SpaceBeforeSquareBrackets: false
-Standard: c++17
+#BitFieldColonSpacing: Both
+Standard: c++20
+StatementAttributeLikeMacros:
+  - Q_EMIT
+  - emit
 StatementMacros:
   - Q_UNUSED
   - QT_REQUIRE_VERSION
@@ -137,5 +175,6 @@ StatementMacros:
 TabWidth: 4
 #UseCRLF: false
 #UseTab: Never
+#WhitespaceSensitiveMacros: [] # Whatever's the default, not using it
 ...
 
diff --git a/.clang-tidy b/.clang-tidy
new file mode 100644
index 00000000..d15c6eb4
--- /dev/null
+++ b/.clang-tidy
@@ -0,0 +1,175 @@
+---
+Checks: '-*,bugprone-argument-comment,bugprone-assert-side-effect,bugprone-bool-pointer-implicit-conversion,bugprone-copy-constructor-init,bugprone-dangling-handle,bugprone-fold-init-type,bugprone-forward-declaration-namespace,bugprone-forwarding-reference-overload,bugprone-inaccurate-erase,bugprone-integer-division,bugprone-lambda-function-name,bugprone-macro-*,bugprone-move-forwarding-reference,bugprone-multiple-statement-macro,bugprone-parent-virtual-call,bugprone-redundant-branch-condition,bugprone-reserved-identifier,bugprone-signed-char-misuse,bugprone-sizeof-*,bugprone-string-*,bugprone-stringview-nullptr,bugprone-suspicious-*,bugprone-swapped-arguments,bugprone-terminating-continue,bugprone-too-small-loop-variable,bugprone-undefined-memory-manipulation,bugprone-undelegated-constructor,bugprone-unhandled-self-assignment,bugprone-unused-*,bugprone-use-after-move,bugprone-virtual-near-miss,cert-dcl50-cpp,cert-dcl58-cpp,cert-dcl59-cpp,cert-env33-c,cert-err33-c,cert-err34-c,cert-err60-cpp,cert-fio38-c,cert-flp30-c,cert-mem57-cpp,cert-msc30-c,cert-msc32-c,cert-msc50-cpp,cert-msc51-cpp,cert-oop57-cpp,cert-oop58-cpp,clang-analyzer-core.CallAndMessage,clang-analyzer-core.DivideZero,clang-analyzer-core.NullDereference,clang-analyzer-core.StackAddrEscapeBase,clang-analyzer-core.StackAddressEscape,clang-analyzer-core.UndefinedBinaryOperatorResult,clang-analyzer-core.uninitialized.*,clang-analyzer-cplusplus.*,clang-analyzer-deadcode.DeadStores,clang-analyzer-optin.cplusplus.*,cppcoreguidelines-c-copy-assignment-signature,cppcoreguidelines-init-variables,cppcoreguidelines-interfaces-global-init,cppcoreguidelines-narrowing-conversions,cppcoreguidelines-no-malloc,cppcoreguidelines-prefer-member-initializer,cppcoreguidelines-pro-bounds-array-to-pointer-decay,cppcoreguidelines-pro-bounds-pointer-arithmetic,cppcoreguidelines-pro-type-cstyle-cast,cppcoreguidelines-pro-type-member-init,cppcoreguidelines-slicing,cppcoreguidelines-special-member-functions,cppcoreguidelines-virtual-class-destructor,google-explicit-constructor,google-readability-namespace-comments,google-runtime-int,misc-*,-misc-definitions-in-headers,modernize-avoid-*,modernize-concat-nested-namespaces,modernize-deprecated-*,modernize-loop-convert,modernize-make-*,modernize-pass-by-value,modernize-raw-string-literal,modernize-redundant-void-arg,modernize-replace-random-shuffle,modernize-return-braced-init-list,modernize-shrink-to-fit,modernize-unary-static-assert,modernize-use-auto,modernize-use-bool-literals,modernize-use-default-member-init,modernize-use-emplace,modernize-use-equals-*,modernize-use-noexcept,modernize-use-nullptr,modernize-use-override,modernize-use-transparent-functors,modernize-use-uncaught-exceptions,modernize-use-using,performance-*,-performance-no-automatic-move,readability-avoid-const-params-in-decls,readability-container-*,readability-convert-member-functions-to-static,readability-delete-null-pointer,readability-duplicate-include,readability-else-after-return,readability-function-*,readability-implicit-bool-conversion,readability-inconsistent-declaration-parameter-name,readability-make-member-function-const,readability-misleading-indentation,readability-misplaced-array-index,readability-non-const-parameter,readability-qualified-auto,readability-redundant-control-flow,readability-redundant-declaration,readability-redundant-function-ptr-dereference,readability-redundant-member-init,readability-redundant-preprocessor,readability-redundant-smartptr-get,readability-redundant-string-*,readability-simplify-*,readability-static-*,readability-string-compare,readability-suspicious-call-argument,readability-uniqueptr-delete-release,readability-uppercase-literal-suffix,readability-use-anyofallof'
+WarningsAsErrors: ''
+HeaderFilterRegex: ''
+AnalyzeTemporaryDtors: false
+FormatStyle:     file
+CheckOptions:
+  - key:             bugprone-argument-comment.IgnoreSingleArgument
+    value:           '1'
+  - key:             bugprone-argument-comment.StrictMode
+    value:           '1'
+  - key:             bugprone-assert-side-effect.AssertMacros
+    value:           assert,NSAssert,NSCAssert,Q_ASSERT,Q_ASSERT_X
+#  - key:             bugprone-assert-side-effect.IgnoredFunctions
+#    value:           ''
+  - key:             bugprone-assert-side-effect.CheckFunctionCalls
+    value:           'true'
+#  - key:             bugprone-dangling-handle.HandleClasses
+#    value:           'std::basic_string_view;std::experimental::basic_string_view'
+#  - key:             bugprone-signed-char-misuse.CharTypdefsToIgnore
+#    value:           ''
+#  - key:             bugprone-signed-char-misuse.DiagnoseSignedUnsignedCharComparisons
+#    value:           'true'
+  - key:             bugprone-sizeof-expression.WarnOnSizeOfIntegerExpression
+    value:           'true'
+  - key:             bugprone-string-constructor.LargeLengthThreshold
+    value:           '8388608'
+  - key:             bugprone-string-constructor.StringNames
+    value:           '::std::basic_string;::std::basic_string_view'
+  - key:             bugprone-string-constructor.WarnOnLargeLength
+    value:           'true'
+#  - key:             bugprone-suspicious-enum-usage.StrictMode
+#    value:           'false'
+#  - key:             bugprone-suspicious-include.HeaderFileExtensions
+#    value:           ';h;hh;hpp;hxx'
+#  - key:             bugprone-suspicious-include.ImplementationFileExtensions
+#    value:           'c;cc;cpp;cxx'
+#  - key:             bugprone-suspicious-missing-comma.SizeThreshold
+#    value:           '5'
+#  - key:             bugprone-suspicious-string-compare.WarnOnLogicalNotComparison
+#    value:           'false'
+#  - key:             bugprone-suspicious-string-compare.StringCompareLikeFunctions
+#    value:           ''
+#  - key:             bugprone-too-small-loop-variable.MagnitudeBitsUpperLimit
+#    value:           '16'
+#  - key:             bugprone-unhandled-self-assignment.WarnOnlyIfThisHasSuspiciousField
+#    value:           'true'
+#  - key:             cert-dcl59-cpp.HeaderFileExtensions
+#    value:           ';h;hh;hpp;hxx'
+#  - key:             cert-msc32-c.DisallowedSeedTypes
+#    value:           'time_t,std::time_t'
+#  - key:             cert-msc51-cpp.DisallowedSeedTypes
+#    value:           'time_t,std::time_t'
+  - key:             cppcoreguidelines-narrowing-conversions.IgnoreConversionFromTypes
+    value:           'size_t;ptrdiff_t;size_type;difference_type'
+#  - key:             cppcoreguidelines-narrowing-conversions.PedanticMode
+#    value:           'false'
+#  - key:             cppcoreguidelines-narrowing-conversions.WarnOnEquivalentBitWidth
+#    value:           'true'
+#  - key:             cppcoreguidelines-narrowing-conversions.WarnOnIntegerToFloatingPointNarrowingConversion
+#    value:           'true'
+  - key:             cppcoreguidelines-narrowing-conversions.WarnWithinTemplateInstantiation
+    value:           'true'
+#  - key:             cppcoreguidelines-pro-type-member-init.UseAssignment
+#    value:           'false'
+#  - key:             cppcoreguidelines-special-member-functions.AllowMissingMoveFunctionsWhenCopyIsDeleted
+#    value:           'false'
+#  - key:             cppcoreguidelines-special-member-functions.AllowSoleDefaultDtor
+#    value:           'false'
+  - key:             google-readability-namespace-comments.SpacesBeforeComments
+    value:           '1'
+  - key:             google-readability-namespace-comments.ShortNamespaceLines
+    value:           '25'
+  - key:             misc-non-private-member-variables-in-classes.IgnoreClassesWithAllMemberVariablesBeingPublic
+    value:           'true'
+#  - key:             misc-non-private-member-variables-in-classes.IgnorePublicMemberVariables
+#    value:           'false'
+#  - key:             modernize-loop-convert.MakeReverseRangeFunction
+#    value:           ''
+#  - key:             modernize-loop-convert.MakeReverseRangeHeader
+#    value:           ''
+#  - key:             modernize-loop-convert.MaxCopySize
+#    value:           '16'
+#  - key:             modernize-loop-convert.NamingStyle
+#    value:           CamelCase
+#  - key:             modernize-loop-convert.UseCxx20ReverseRanges
+#    value:           'true'
+#  - key:             modernize-make-shared.IgnoreMacros
+#    value:           'true'
+#  - key:             modernize-make-shared.IgnoreDefaultInitialization
+#    value:           'true'
+#  - key:             modernize-make-unique.IgnoreMacros
+#    value:           'true'
+#  - key:             modernize-make-unique.IgnoreDefaultInitialization
+#    value:           'true'
+  - key:             modernize-use-auto.MinTypeNameLength
+    value:           '0'
+#  - key:             modernize-use-auto.RemoveStars
+#    value:           'false'
+#  - key:             modernize-use-bool-literals.IgnoreMacros
+#    value:           'true'
+#  - key:             modernize-use-default-member-init.IgnoreMacros
+#    value:           'true'
+  - key:             modernize-use-default-member-init.UseAssignment
+    value:           'true'
+#  - key:             modernize-use-emplace.SmartPointers
+#    value:           '::std::shared_ptr;::std::unique_ptr;::std::auto_ptr;::std::weak_ptr'
+  - key:             modernize-use-emplace.TupleMakeFunctions
+    value:           '::std::make_pair;::std::make_tuple'
+#  - key:             modernize-use-emplace.TupleTypes
+#    value:           '::std::pair;::std::tuple'
+#  - key:             modernize-use-equals-default.IgnoreMacros
+#    value:           'true'
+#  - key:             modernize-use-equals-delete.IgnoreMacros
+#    value:           'true'
+#  - key:             modernize-use-noexcept.UseNoexceptFalse
+#    value:           'true'
+#  - key:             modernize-use-using.IgnoreMacros
+#    value:           'true'
+  - key:             modernize-raw-string-literal.DelimiterStem
+    value:           ''
+#  - key:             modernize-raw-string-literal.ReplaceShorterLiterals
+#    value:           'false'
+#  - key:             performance-faster-string-find.StringLikeClasses
+#    value:           '::std::basic_string;::std::basic_string_view'
+#  - key:             performance-for-range-copy.AllowedTypes
+#    value:           ''
+#  - key:             performance-for-range-copy.WarnOnAllAutoCopies
+#    value:           'false'
+#  - key:             performance-inefficient-string-concatenation.StrictMode
+#    value:           'false'
+  - key:             performance-inefficient-vector-operation.VectorLikeClasses
+    value:           '::std::vector,QVector,::std::deque'
+#  - key:             performance-unnecessary-copy-initialization.AllowedTypes
+#    value:           ''
+  - key:             readability-else-after-return.WarnOnConditionVariables
+    value:           'true'
+#  - key:             readability-else-after-return.WarnOnUnfixable
+#    value:           'true'
+#  - key:             readability-function-size.StatementThreshold
+#    value:           '800'
+#  - key:             readability-function-cognitive-complexity.DescribeBasicIncrements
+#    value:           'true'
+#  - key:             readability-function-cognitive-complexity.IgnoreMacros
+#    value:           'true'
+#  - key:             readability-function-cognitive-complexity.Threshold
+#    value:           '25'
+#  - key:             readability-implicit-bool-conversion.AllowIntegerConditions
+#    value:           'false'
+  - key:             readability-implicit-bool-conversion.AllowPointerConditions
+    value:           'true'
+#  - key:             readability-inconsistent-declaration-parameter-name.IgnoreMacros
+#    value:           'true'
+  - key:             readability-inconsistent-declaration-parameter-name.Strict
+    value:           'true'
+#  - key:             readability-qualified-auto.AddConstToQualified
+#    value:           'true'
+#  - key:             readability-redundant-declaration.IgnoreMacros
+#    value:           'true'
+#  - key:             readability-redundant-member-init.IgnoreBaseInCopyConstructors
+#    value:           'false'
+#  - key:             readability-redundant-smartptr-get.IgnoreMacros
+#    value:           'true'
+  - key:             readability-simplify-boolean-expr.ChainedConditionalAssignment
+    value:           'true'
+  - key:             readability-simplify-boolean-expr.ChainedConditionalReturn
+    value:           'true'
+#  - key:             readability-uniqueptr-delete-release.PreferResetCall
+#    value:           'false'
+#  - key:             readability-uppercase-literal-suffix.IgnoreMacros
+#    value:           'true'
+  - key:             readability-uppercase-literal-suffix.NewSuffixes
+    value:           'f;F'
+...
+
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b704b3b9..f84356b0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,44 +14,65 @@ concurrency: ci-${{ github.ref }}
 jobs:
   CI:
     runs-on: ${{ matrix.os }}
-    continue-on-error: ${{ matrix.update-api != '' }} # the current upstream API definitions are expected to fail the test
+    continue-on-error: ${{ matrix.qt-version != '5.15.2' }} # Qt 6 will fail for now
     strategy:
       fail-fast: false
       max-parallel: 1
       matrix:
-        os: [ ubuntu-20.04, macos-10.15 ]
-        compiler: [ GCC, Clang ]
-        qt-version: [ '5.12.12' ]
+        os: [ ubuntu-20.04, macos-11 ]
+        qt-version: [ '6.3.1', '5.15.2' ]
+        compiler: [ LLVM ]
         # Not using binary values here, to make the job captions more readable
         e2ee: [ '', e2ee ]
         update-api: [ '', update-api ]
-        sonar: [ '' ]
+        static-analysis: [ '' ]
         platform: [ '' ]
         qt-arch: [ '' ]
         exclude:
-        - os: macos-10.15
-          compiler: GCC
-        - os: windows-2019
-          e2ee: e2ee # Not supported by the current CI script
-        - os: macos-10.15
-          e2ee: e2ee # Missing OpenSSL
+        - qt-version: '6.3.1'
+          update-api: update-api # Generated code is not specific to Qt version
+        - os: ubuntu-20.04
+          e2ee: e2ee # Will be re-added with static analysis below
+        # TODO: Enable E2EE on Windows and macOS
+        - os: macos-11
+          e2ee: e2ee
         include:
-        - os: ubuntu-latest
+        - os: windows-2019
+          qt-version: '5.15.2'
+          compiler: MSVC
+          platform: x64
+          qt-arch: win64_msvc2019_64
+        - os: ubuntu-20.04
+          qt-version: '5.15.2'
+          compiler: LLVM
+          e2ee: e2ee
+          static-analysis: codeql
+        - os: ubuntu-22.04
+          qt-version: '5.15.2'
+          compiler: GCC
+          e2ee: e2ee
+          static-analysis: sonar
+        - os: ubuntu-22.04
+          qt-version: '5.15.2'
           compiler: GCC
-          qt-version: '5.12.12'
           e2ee: e2ee
-          sonar: sonar
+          update-api: update-api
+        - os: ubuntu-20.04
+          qt-version: '5.15.2'
+          compiler: LLVM
+          update-api: update-api
         - os: windows-2019
+          qt-version: '6.3.1'
           compiler: MSVC
+          # e2ee: e2ee # TODO
           platform: x64
-          qt-version: '5.12.12'
-          qt-arch: win64_msvc2017_64
+          qt-arch: win64_msvc2019_64
         - os: windows-2019
+          qt-version: '5.15.2'
           compiler: MSVC
-          platform: x64
-          qt-version: '5.12.12'
-          qt-arch: win64_msvc2017_64
           update-api: update-api
+          platform: x64
+          qt-arch: win64_msvc2019_64
 
     env:
       SONAR_SERVER_URL: 'https://sonarcloud.io'
@@ -69,36 +90,25 @@ jobs:
         key: ${{ runner.os }}${{ matrix.platform }}-Qt${{ matrix.qt-version }}-cache
 
     - name: Install Qt
-      uses: jurplel/install-qt-action@v2.11.1
+      uses: jurplel/install-qt-action@v2.14.0
       with:
         version: ${{ matrix.qt-version }}
         arch: ${{ matrix.qt-arch }}
         cached: ${{ steps.cache-qt.outputs.cache-hit }}
 
-    - name: Install Ninja (macOS/Windows)
-      if: ${{ !startsWith(matrix.os, 'ubuntu') }}
-      uses: seanmiddleditch/gha-setup-ninja@v3
-
-    - name: Install Ninja and Valgrind (Linux)
-      if: startsWith(matrix.os, 'ubuntu')
-      run: |
-        sudo apt-get -qq install ninja-build valgrind
-        echo "VALGRIND=valgrind --tool=memcheck --leak-check=yes --gen-suppressions=all --suppressions=$GITHUB_WORKSPACE/quotest/.valgrind.supp" >>$GITHUB_ENV
-
     - name: Setup build environment
       run: |
-        if [ "${{ matrix.compiler }}" == "GCC" ]; then
-            CXX_VERSION_POSTFIX='-10'
-            echo "CC=gcc$CXX_VERSION_POSTFIX" >>$GITHUB_ENV
-            echo "CXX=g++$CXX_VERSION_POSTFIX" >>$GITHUB_ENV
-        elif [[ '${{ matrix.compiler }}' == 'Clang' ]]; then
-            if [[ '${{ runner.os }}' == 'Linux' ]]; then
-                CXX_VERSION_POSTFIX='-11'
-                # Do CodeQL analysis on one of Linux branches
-                echo "CODEQL_ANALYSIS=true" >>$GITHUB_ENV
+        if [ '${{ matrix.compiler }}' == 'GCC' ]; then
+            echo "CC=gcc" >>$GITHUB_ENV
+            echo "CXX=g++" >>$GITHUB_ENV
+            if [ '${{ startsWith(matrix.qt-version, '5') }}' == 'true' ]; then
+                # Patch Qt to avoid GCC tumbling over QTBUG-90568/QTBUG-91909
+                sed -i 's/ThreadEngineStarter<void>(ThreadEngine<void> \*_threadEngine)/ThreadEngineStarter(ThreadEngine<void> \*_threadEngine)/' \
+                    $Qt5_DIR/include/QtConcurrent/qtconcurrentthreadengine.h
             fi
-            echo "CC=clang$CXX_VERSION_POSTFIX" >>$GITHUB_ENV
-            echo "CXX=clang++$CXX_VERSION_POSTFIX" >>$GITHUB_ENV
+        elif [[ '${{ runner.os }}' != 'Windows' ]]; then
+            echo "CC=clang" >>$GITHUB_ENV
+            echo "CXX=clang++" >>$GITHUB_ENV
         fi
         if grep -q 'refs/tags' <<<'${{ github.ref }}'; then
             VERSION="$(git describe --tags)"
@@ -107,20 +117,19 @@ jobs:
         else
             VERSION="$(git describe --all --contains)-ci${{ github.run_number }}-$(git rev-parse --short HEAD)"
         fi
-        echo "QUOTEST_ORIGIN=$VERSION @ ${{ runner.os }}/${{ matrix.compiler }}" >>$GITHUB_ENV
 
-        # Build libQuotient as a shared library across platforms but also
-        # check the static configuration somewhere
+        echo "QUOTEST_ORIGIN=$VERSION @ ${{ runner.os }}/Qt-${{ matrix.qt-version }}/${{ matrix.compiler }}" >>$GITHUB_ENV
+
         CMAKE_ARGS="-G Ninja -DCMAKE_BUILD_TYPE=RelWithDebInfo \
                     -DBUILD_SHARED_LIBS=${{ runner.os == 'Linux' }} \
                     -DCMAKE_INSTALL_PREFIX=~/.local \
                     -DCMAKE_PREFIX_PATH=~/.local \
-                    -DCMAKE_INSTALL_RPATH_USE_LINK_PATH=ON"
+                    -DCMAKE_INSTALL_RPATH_USE_LINK_PATH=ON \
+                    -DBUILD_WITH_QT6=${{ startsWith(matrix.qt-version, '6') }}"
 
-        if [ -n "${{ matrix.sonar }}" ]; then
+        if [ '${{ matrix.static-analysis }}' == 'sonar' ]; then
             mkdir -p $HOME/.sonar
             CMAKE_ARGS="$CMAKE_ARGS -DCMAKE_CXX_FLAGS=--coverage"
-            echo "COV=gcov$CXX_VERSION_POSTFIX" >>$GITHUB_ENV
         fi
         echo "CMAKE_ARGS=$CMAKE_ARGS" >>$GITHUB_ENV
 
@@ -134,14 +143,28 @@ jobs:
         cmake -E make_directory ${{ runner.workspace }}/build
         echo "BUILD_PATH=${{ runner.workspace }}/build/libQuotient" >>$GITHUB_ENV
 
-    - name: Setup MSVC environment
+    - name: Install Ninja (macOS/Windows)
+      if: ${{ !startsWith(matrix.os, 'ubuntu') }}
+      uses: seanmiddleditch/gha-setup-ninja@v3
+
+    - name: Install dependencies (Linux)
+      if: startsWith(matrix.os, 'ubuntu')
+      run: |
+        if [ -n "${{ matrix.e2ee }}" ]; then
+            EXTRA_DEPS="libssl-dev libolm-dev"
+            echo "QUOTEST_ORIGIN=$QUOTEST_ORIGIN with E2EE" >>$GITHUB_ENV
+        fi
+        sudo apt-get -qq install ninja-build valgrind $EXTRA_DEPS
+        echo "VALGRIND=valgrind --tool=memcheck --leak-check=yes --gen-suppressions=all --suppressions=$GITHUB_WORKSPACE/quotest/.valgrind.supp" >>$GITHUB_ENV
+
+    - name: Setup MSVC
       uses: ilammy/msvc-dev-cmd@v1
       if: matrix.compiler == 'MSVC'
       with:
         arch: ${{ matrix.platform }}
 
     - name: Download and set up Sonar Cloud tools
-      if: matrix.sonar != ''
+      if: matrix.static-analysis == 'sonar'
       env:
         SONAR_SCANNER_VERSION: 4.6.2.2472
       run: |
@@ -154,43 +177,28 @@ jobs:
         unzip -o sonar-scanner-cli*.zip
         popd
 
-    - name: Install OpenSSL
-      if: ${{ contains(matrix.os, 'ubuntu') && matrix.e2ee }}
-      run: |
-        sudo apt-get install libssl-dev
-
-    - name: Build and install olm
-      if: matrix.e2ee
-      working-directory: ${{ runner.workspace }}
-      run: |
-        git clone https://gitlab.matrix.org/matrix-org/olm.git
-        cmake -S olm -B build/olm $CMAKE_ARGS
-        cmake --build build/olm --target install
-        echo "QUOTEST_ORIGIN=$QUOTEST_ORIGIN with E2EE" >>$GITHUB_ENV
-
     - name: Build and install QtKeychain
       run: |
         cd ..
-        git clone https://github.com/frankosterfeld/qtkeychain.git
+        git clone -b v0.13.2 https://github.com/frankosterfeld/qtkeychain.git
         cmake -S qtkeychain -B qtkeychain/build $CMAKE_ARGS
         cmake --build qtkeychain/build --target install
 
-    - name: Pull CS API and build GTAD
+    - name: get CS API definitions; clone and build GTAD
       if: matrix.update-api
-      working-directory: ${{ runner.workspace }}
       run: |
-        git clone https://github.com/matrix-org/matrix-doc.git
-        git clone --recursive https://github.com/KitsuneRal/gtad.git
-        cmake -S gtad -B build/gtad $CMAKE_ARGS -DBUILD_SHARED_LIBS=OFF
-        cmake --build build/gtad
-        echo "CMAKE_ARGS=$CMAKE_ARGS -DMATRIX_DOC_PATH=${{ runner.workspace }}/matrix-doc \
+        git clone --depth=1 https://github.com/quotient-im/matrix-spec.git ../matrix-spec
+        git submodule update --init --recursive --depth=1
+        cmake -S gtad/gtad -B ../build/gtad $CMAKE_ARGS -DBUILD_SHARED_LIBS=OFF
+        cmake --build ../build/gtad
+        echo "CMAKE_ARGS=$CMAKE_ARGS -DMATRIX_SPEC_PATH=${{ runner.workspace }}/matrix-spec \
                                      -DGTAD_PATH=${{ runner.workspace }}/build/gtad/gtad" \
              >>$GITHUB_ENV
         echo "QUOTEST_ORIGIN=$QUOTEST_ORIGIN with API files regeneration" >>$GITHUB_ENV
 
     - name: Initialize CodeQL tools
-      if: env.CODEQL_ANALYSIS
-      uses: github/codeql-action/init@v1
+      if: matrix.static-analysis == 'codeql'
+      uses: github/codeql-action/init@v2
       with:
         languages: cpp
         # If you wish to specify custom queries, you can do so here or in a config file.
@@ -232,18 +240,18 @@ jobs:
       timeout-minutes: 4 # quotest is supposed to finish within 3 minutes, actually
 
     - name: Perform CodeQL analysis
-      if: env.CODEQL_ANALYSIS
-      uses: github/codeql-action/analyze@v1
+      if: matrix.static-analysis == 'codeql'
+      uses: github/codeql-action/analyze@v2
 
     - name: Run sonar-scanner
-      if: matrix.sonar != ''
+      if: matrix.static-analysis == 'sonar'
       env:
         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
       run: |
         mkdir .coverage && pushd .coverage
         find $BUILD_PATH -name '*.gcda' -print0 \
-            | xargs -0 $COV -s $GITHUB_WORKSPACE -pr
+            | xargs -0 gcov -s $GITHUB_WORKSPACE -pr
         # Coverage of the test source code is not tracked, as it is always 100%
         # (if not, some tests failed and broke the build at an earlier stage)
         rm -f quotest* autotests*
diff --git a/.gitmodules b/.gitmodules
index e69de29b..f3aef316 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "gtad/gtad"]
+	path = gtad/gtad
+	url = https://github.com/quotient-im/gtad.git
diff --git a/.lgtm.yml b/.lgtm.yml
deleted file mode 100644
index a01e1de9..00000000
--- a/.lgtm.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-path_classifiers:
-  library:
-  - 3rdparty/*
-  test:
-  - exclude: tests/quotest.cpp # Let alerts from this come up too
-extraction:
-  cpp:
-    prepare:
-      packages: # Assuming package base of eoan
-      - qtmultimedia5-dev
-#    after_prepare:
-#    - git clone https://gitlab.matrix.org/matrix-org/olm.git
-#    - pushd olm
-#    - cmake . -Bbuild -GNinja
-#    - cmake --build build
-#    - popd
-    configure:
-      command: "CXX=clang++-9 cmake . -GNinja" # -DOlm_DIR=olm/build"
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1030e12d..7aebe070 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,4 @@
-# Officially CMake 3.16+ is needed but LGTM.com still sits on eoan that only
-# has CMake 3.13
-cmake_minimum_required(VERSION 3.13)
+cmake_minimum_required(VERSION 3.16)
 if (POLICY CMP0092)
 cmake_policy(SET CMP0092 NEW)
 endif()
@@ -40,7 +38,7 @@ if (MSVC)
         /wd4710 /wd4774 /wd4820 /wd4946 /wd5026 /wd5027)
 else()
     foreach (FLAG Wall Wpedantic Wextra Werror=return-type Wno-unused-parameter
-            Wno-gnu-zero-variadic-macro-arguments)
+            Wno-gnu-zero-variadic-macro-arguments Wno-subobject-linkage)
         CHECK_CXX_COMPILER_FLAG("-${FLAG}" COMPILER_${FLAG}_SUPPORTED)
         if ( COMPILER_${FLAG}_SUPPORTED AND
                 NOT CMAKE_CXX_FLAGS MATCHES "(^| )-?${FLAG}($| )")
@@ -80,7 +78,7 @@ option(BUILD_WITH_QT6 "Build Quotient with Qt 6 (EXPERIMENTAL)" OFF)
 if (BUILD_WITH_QT6)
     set(QtMinVersion "6.0")
 else()
-    set(QtMinVersion "5.12")
+    set(QtMinVersion "5.15")
     set(QtExtraModules "Multimedia") # See #483
 endif()
 string(REGEX REPLACE "^(.).*" "Qt\\1" Qt ${QtMinVersion}) # makes "Qt5" or "Qt6"
@@ -88,6 +86,8 @@ find_package(${Qt} ${QtMinVersion} REQUIRED Core Network Gui Test ${QtExtraModul
 get_filename_component(Qt_Prefix "${${Qt}_DIR}/../../../.." ABSOLUTE)
 message(STATUS "Using Qt ${${Qt}_VERSION} at ${Qt_Prefix}")
 
+find_package(${Qt}Keychain REQUIRED)
+
 if (${PROJECT_NAME}_ENABLE_E2EE)
     find_package(${Qt} ${QtMinVersion} REQUIRED Sql)
     find_package(Olm 3.1.3 REQUIRED)
@@ -109,7 +109,6 @@ if (${PROJECT_NAME}_ENABLE_E2EE)
     if (OpenSSL_FOUND)
         message(STATUS "Using OpenSSL ${OpenSSL_VERSION} at ${OpenSSL_DIR}")
     endif()
-    find_package(${Qt}Keychain REQUIRED)
 endif()
 
 
@@ -119,6 +118,7 @@ list(APPEND lib_SRCS
     lib/quotient_export.h
     lib/function_traits.h lib/function_traits.cpp
     lib/omittable.h
+    lib/expected.h
     lib/networkaccessmanager.h lib/networkaccessmanager.cpp
     lib/connectiondata.h lib/connectiondata.cpp
     lib/connection.h lib/connection.cpp
@@ -144,6 +144,7 @@ list(APPEND lib_SRCS
     lib/events/eventloader.h
     lib/events/roomevent.h lib/events/roomevent.cpp
     lib/events/stateevent.h lib/events/stateevent.cpp
+    lib/events/single_key_value.h
     lib/events/simplestateevents.h
     lib/events/eventcontent.h lib/events/eventcontent.cpp
     lib/events/eventrelation.h lib/events/eventrelation.cpp
@@ -151,6 +152,7 @@ list(APPEND lib_SRCS
     lib/events/roomtombstoneevent.h lib/events/roomtombstoneevent.cpp
     lib/events/roommessageevent.h lib/events/roommessageevent.cpp
     lib/events/roommemberevent.h lib/events/roommemberevent.cpp
+    lib/events/roomcanonicalaliasevent.h
     lib/events/roomavatarevent.h
     lib/events/roompowerlevelsevent.h lib/events/roompowerlevelsevent.cpp
     lib/events/typingevent.h lib/events/typingevent.cpp
@@ -165,9 +167,9 @@ list(APPEND lib_SRCS
     lib/events/encryptionevent.h lib/events/encryptionevent.cpp
     lib/events/encryptedevent.h lib/events/encryptedevent.cpp
     lib/events/roomkeyevent.h lib/events/roomkeyevent.cpp
-    lib/events/stickerevent.h lib/events/stickerevent.cpp
-    lib/events/keyverificationevent.h lib/events/keyverificationevent.cpp
-    lib/events/encryptedfile.h lib/events/encryptedfile.cpp
+    lib/events/stickerevent.h
+    lib/events/keyverificationevent.h
+    lib/events/filesourceinfo.h lib/events/filesourceinfo.cpp
     lib/jobs/requestdata.h lib/jobs/requestdata.cpp
     lib/jobs/basejob.h lib/jobs/basejob.cpp
     lib/jobs/syncjob.h lib/jobs/syncjob.cpp
@@ -198,20 +200,23 @@ set(ASAPI_DEF_DIR application-service/definitions)
 set(ISAPI_DEF_DIR identity/definitions)
 
 set(API_GENERATION_ENABLED 0)
-if (GTAD_PATH AND MATRIX_DOC_PATH)
+if (NOT MATRIX_SPEC_PATH AND MATRIX_DOC_PATH)
+    set(MATRIX_SPEC_PATH ${MATRIX_DOC_PATH})
+endif()
+if (GTAD_PATH AND MATRIX_SPEC_PATH)
     # REALPATH resolves ~ (home directory) while PROGRAM doesn't
     get_filename_component(ABS_GTAD_PATH "${GTAD_PATH}" REALPATH)
     get_filename_component(ABS_GTAD_PATH "${ABS_GTAD_PATH}" PROGRAM PROGRAM_ARGS GTAD_ARGS)
     if (EXISTS ${ABS_GTAD_PATH})
-        get_filename_component(ABS_API_DEF_PATH "${MATRIX_DOC_PATH}/data/api" REALPATH)
+        get_filename_component(ABS_API_DEF_PATH "${MATRIX_SPEC_PATH}/data/api" REALPATH)
         if (NOT IS_DIRECTORY ${ABS_API_DEF_PATH})
             # Check the old place of API files
-            get_filename_component(ABS_API_DEF_PATH "${MATRIX_DOC_PATH}/api" REALPATH)
+            get_filename_component(ABS_API_DEF_PATH "${MATRIX_SPEC_PATH}/api" REALPATH)
         endif ()
         if (IS_DIRECTORY ${ABS_API_DEF_PATH})
             set(API_GENERATION_ENABLED 1)
         else ()
-            message( WARNING "${MATRIX_DOC_PATH} doesn't seem to point to a valid matrix-doc repo; disabling API stubs generation")
+            message( WARNING "${MATRIX_SPEC_PATH} doesn't seem to point to a valid matrix-doc repo; disabling API stubs generation")
         endif ()
     else (EXISTS ${ABS_GTAD_PATH})
         message( WARNING "${GTAD_PATH} is not executable; disabling API stubs generation")
@@ -291,13 +296,10 @@ set_target_properties(${PROJECT_NAME} PROPERTIES
 set_property(TARGET ${PROJECT_NAME} APPEND PROPERTY
              COMPATIBLE_INTERFACE_STRING ${PROJECT_NAME}_MAJOR_VERSION)
 
-# C++17 required, C++20 desired (see above)
-target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_17)
+target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_20)
 
-# TODO: Bump the CMake requirement and drop the version check here once
-# LGTM upgrades
-if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.16.0"
-        AND NOT CMAKE_CXX_COMPILER_ID STREQUAL GNU) # https://bugzilla.redhat.com/show_bug.cgi?id=1721553
+# Don't use PCH w/GCC (https://bugzilla.redhat.com/show_bug.cgi?id=1721553#c34)
+if (NOT CMAKE_CXX_COMPILER_ID STREQUAL GNU)
     target_precompile_headers(${PROJECT_NAME} PRIVATE lib/converters.h)
 endif ()
 
@@ -309,14 +311,14 @@ if (${PROJECT_NAME}_ENABLE_E2EE)
     target_link_libraries(${PROJECT_NAME} Olm::Olm
         OpenSSL::Crypto
         OpenSSL::SSL
-        ${Qt}::Sql
-        ${QTKEYCHAIN_LIBRARIES})
+        ${Qt}::Sql)
     set(FIND_DEPS "find_dependency(Olm)
     find_dependency(OpenSSL)
     find_dependency(${Qt}Sql)") # For QuotientConfig.cmake.in
 endif()
 
-target_link_libraries(${PROJECT_NAME} ${Qt}::Core ${Qt}::Network ${Qt}::Gui)
+target_include_directories(${PROJECT_NAME} PRIVATE ${QTKEYCHAIN_INCLUDE_DIRS})
+target_link_libraries(${PROJECT_NAME} ${Qt}::Core ${Qt}::Network ${Qt}::Gui ${QTKEYCHAIN_LIBRARIES})
 
 if (Qt STREQUAL Qt5) # See #483
     target_link_libraries(${PROJECT_NAME} ${Qt}::Multimedia)
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 3eeac68c..fb10c7da 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -35,8 +35,8 @@ See the GitHub Help [articles about pull requests](https://help.github.com/artic
 to learn how to deal with them.
 
 We recommend creating different branches for different (logical)
-changes, and creating a pull request when you're done into the master branch.
-See the GitHub documentation on
+changes, and creating a pull request when you're done; the development
+integration branch is `dev`. See the GitHub documentation on
 [creating branches](https://help.github.com/articles/creating-and-deleting-branches-within-your-repository/)
 and
 [using pull requests](https://help.github.com/articles/using-pull-requests/).
@@ -133,10 +133,9 @@ unfortunately this other algorithm is *also* called GitHub-flavoured markdown.
 In your markdown, please don't use tab characters and avoid "bare" URLs.
 In a hyperlink, the link text and URL should be on the same line.
 While historically we didn't care about the line length in markdown texts
-(and more often than not put the whole paragraph into one line), this is subject
-to change anytime soon, with 80-character limit _recommendation_
-(which is softer than the limit for C/C++ code) imposed on everything
-_except hyperlinks_ (because wrapping hyperlinks breaks the rendering).
+(and more often than not put the whole paragraph into one line), this is no more
+recommended; instead, try to use 80-character limit (similar to the limit for
+C/C++ code) _except hyperlinks_ - wrapping breaks them.
 
 Do not use trailing two spaces for line breaks, since these cannot be seen
 and may be silently removed by some tools. If, for whatever reason, a blank line
@@ -155,20 +154,7 @@ just don't bankrupt us with it. Refactoring is welcome.
 
 ### Code style and formatting
 
-As of Quotient 0.6, the C++ standard for newly written code is C++17 with C++20
-compatibility and a few restrictions, notably:
-* standard library's _deduction guides_ cannot be used to lighten up syntax
-  in template instantiation, i.e. you have to still write
-  `std::array<int, 2> { 1, 2 }` instead of `std::array { 1, 2 }` (or use
-  `Quotient::make_array` helper from `util.h`), use `std::make_pair` to create
-  pairs etc. - once we move over to the later Apple toolchain, this will be
-  no more necessary;
-* enumerators and slots cannot have `[[attributes]]` because moc from Qt 5.12
-  chokes on them - this will be lifted when we move on to Qt 5.13 for the oldest
-  supported version, in the meantime use `Q_DECL_DEPRECATED` and similar Qt
-  macros - they expand to nothing when the code is passed to moc.
-* explicit lists in lambda captures are preferred over `[=]`; note that C++20
-  deprecates implicit `this` capture in `[=]`.
+As of Quotient 0.7, the C++ standard for newly written code is C++20.
 
 The code style is defined by `.clang-format`, and in general, all C++ files
 should follow it. Files with minor deviations from the defined style are still
@@ -176,11 +162,13 @@ accepted in PRs; however, unless explicitly marked with `// clang-format off`
 and `// clang-format on`, these deviations will be rectified any commit soon
 after.
 
-Additional considerations:
+Notable things from .clang-format:
 * 4-space indents, no tabs, no trailing spaces, no last empty lines. If you
   spot the code abusing these - thank you for fixing it.
 * Prefer keeping lines within 80 characters. Slight overflows are ok only
   if that helps readability.
+  
+Additionally:
 * Please don't make "hypocritical structs" with protected or private members.
   In general, `struct` is used to denote a plain-old-data structure, rather
   than data+behaviour. If you need access control or are adding yet another
@@ -195,25 +183,25 @@ Additional considerations:
   * `std::array` and `std::deque` have no direct counterparts in Qt.
   * Because of COW semantics, Qt containers cannot hold uncopyable classes.
     Classes without a default constructor are a problem too. Examples of that
-    are `SyncRoomData` and `EventsArray<>`. Use STL containers for those but
-    see the next point and also consider if you can supply a reasonable
-    copy/default constructor.
+    are `SyncRoomData` and `EventsArray<>`. Use STL containers for structures
+    having those but see the next point and also consider if you can supply
+    a reasonable copy/default constructor.
   * STL containers can be freely used in code internal to a translation unit
     (i.e., in a certain .cpp file) _as long as that is not exposed in the API_.
     It's ok to use, e.g., `std::vector` instead of `QVector` to tighten up
     code where you don't need COW, or when dealing with uncopyable
     data structures (see the previous point). However, exposing STL containers
     in the API is not encouraged (except where absolutely necessary, e.g. we use
-    `std::deque` for a timeline). Exposing STL containers or iterators in API
-    intended for usage by QML code (e.g. in `Q_PROPERTY`) is unlikely to work
-    and therefore unlikely to be accepted into `master`.
-  * Prefer using `std::unique_ptr<>` over `QScopedPointer<>` as it gives
-    stronger guarantees. Earlier revisions of this text recommended using
-    `QScopedPointer<>` because Qt Creator's debugger UI had a display helper
-    for it; it now has helpers for both.
-* Use `QVector` instead of `QList` where possible - see the
+    `std::deque` for a timeline). Especially when it comes to API intended
+    for usage from QML (e.g. `Q_PROPERTY`), STL containers or iterators are
+    unlikely to work and therefore unlikely to be accepted into `dev`.
+  * Notwithstanding the above (you're not going to use them with QML anyway),
+    prefer `std::unique_ptr<>` over `QScopedPointer<>` as it gives stronger
+    guarantees.
+* Always use `QVector` instead of `QList` unless Qt's own API uses it - see the
   [great article by Marc Mutz on Qt containers](https://marcmutz.wordpress.com/effective-qt/containers/)
-  for details.
+  for details. With Qt 6, these two become the same type matching what used
+  to be `QVector` in Qt 5.
 
 ### API conventions
 
@@ -231,23 +219,24 @@ this may change eventually.
 ### Comments
 
 Whenever you add a new call to the library API that you expect to be used
-from client code, you must supply a proper doc-comment along with the call.
-Doxygen style is preferred; but Javadoc is acceptable too. Some parts are
-not documented at all; adding doc-comments to them is highly encouraged.
+from client code, make sure to supply a proper doc-comment along with the call.
+Quotient uses the Doxygen style; some legacy code may use Javadoc style but it
+is not encouraged any more. Some parts are not documented at all;
+adding doc-comments to them is highly encouraged and is a great first-time
+contribution.
 
 Use `\brief` for the summary, and follow with details after
-an empty doc-comment line.
+an empty doc-comment line, using `\param`, `\return` etc. as necessary.
 
 For in-code comments, the advice is as follows:
 * Don't restate what's happening in the code unless it's not really obvious.
-  We assume the readers to have at least some command of C++ and Qt. If your
-  code is not obvious, consider making it clearer itself before commenting.
-* Both C++ and Qt still come with their arcane features and dark corners,
+  We assume the readers to have some command of C++ and Qt. If your code is
+  not obvious, consider making it clearer itself before commenting.
+* That said, both C++ and Qt have their arcane features and dark corners,
   and we don't want to limit anybody who feels they have a case for
-  variable templates, raw literals, or use `std::as_const` to avoid container
-  detachment. Use your experience to figure what might be less well-known to
-  readers and comment such cases (references to web pages, Quotient wiki etc.
-  are very much ok, the previous bullet notwithstanding).
+  variadic templates, raw literals, and so on. Use your experience to figure
+  what might be less well-known to readers and comment such cases: leave
+  references to web pages, Quotient wiki etc.
 * Make sure to document not so much "what" but more "why" certain code is done
   the way it is. In the worst case, the logic of the code can be
   reverse-engineered; but you can almost never reverse-engineer the line of
@@ -255,26 +244,43 @@ For in-code comments, the advice is as follows:
 
 ### Automated tests
 
-There's no testing framework as of now; either Catch or Qt Test or both will
-be used eventually.
-
-The `tests/` directory contains a command-line program, quotest, used for
-automated functional testing. Any significant addition to the library API
-should be accompanied by a respective test in quotest. To add a test you should:
-- Add a new test to the `TestSuite` class (technically, each test is a private
-  slot and there are two macros, `TEST_DECL()` and `TEST_IMPL()`, that conceal
-  passing the testing handle in `thisTest` variable to the test method).
-- Add test logic to the slot, using `FINISH_TEST` macro to assert the test
-  outcome and complete the test (`FINISH_TEST` contains `return`). ALL
-  (even failing) branches should conclude with a `FINISH_TEST` (or `FAIL_TEST`
-  that is a shortcut for a failing `FINISH_TEST`) invocation, unless you
-  intend to have a "DID NOT FINISH" message in the logs in certain conditions.
+We gradually introduce autotests based on a combination of CTest and Qt Test
+frameworks - see `autotests/` directory. There are very few of those, as we
+have just started adding those to the new code (you guessed it; adding more
+tests to the old code is very welcome).
+
+Aside from that, libQuotient comes with a command-line end-to-end test suite
+called Quotest. Any significant addition to the library API should be
+accompanied by a respective test in `autotests/` and/or in Quotest.
+
+To add a test to autotests:
+- In a new .cpp file in `autotests/`, define a test class derived from
+  QObject with `private Q_SLOTS:` section having the member functions called
+  for testing. If you feel more comfortable using a header file to define
+  the class, feel free to do so. If you're new to Qt Test framework, use
+  existing tests as a guidance.
+- Add a `quotient_add_test` macro call with your test to
+  `autotests/CMakeLists.txt`
+
+To add a test to Quotest:
+- In `quotest.cpp`, add a new test to the `TestSuite` class. Similar to Qt Test,
+  each test in Quotest is a private slot; unlike Qt Test, you should use
+  special macros, `TEST_DECL()` and `TEST_IMPL()`, to declare and define
+  the test (those macros conceal passing the testing handle in `thisTest`
+  variable to the test method).
+- In the test function definition, add test logic using `FINISH_TEST` macro
+  to check for the test outcome and complete the test (be mindful that
+  `FINISH_TEST` always `return`s, not only in case of error). ALL (even failing)
+  branches should conclude with a `FINISH_TEST` (or `FAIL_TEST` that is
+  a shortcut for a failing `FINISH_TEST`) invocation, unless you intend to have
+  a "DID NOT FINISH" message in the logs in certain conditions.
 
 The `TestManager` class sets up some basic test fixture to help you with testing;
-notably, the tests can rely on having an initialised `Room` object for the test
-room in `targetRoom` member variable. PRs to introduce a proper testing framework
-are very welcome (make sure to migrate tests from quotest though). Note that
-tests can go async, which is the biggest hurdle for Qt Test adoption.
+notably, the tests can rely on having an initialised `Room` object with loaded
+state for the test room in `targetRoom` member variable. Note that it's normal
+for tests to go async, which is not something Qt Test is easy with (and this
+is why Quotest doesn't directly use Qt Test but rather fetches a few ideas
+from it).
 
 ### Security, privacy, and performance
 
@@ -306,13 +312,15 @@ this trend.
 We want the software to have decent performance for users even on weaker
 machines. At the same time we keep libQuotient single-threaded as much
 as possible, to keep the code simple. That means being cautious about operation
-complexity (read about big-O notation if you need a kickstart on the topic).
+complexity (read about big-O notation if you need a kickstart on the subject).
 This especially refers to operations on the whole timeline and the list of
 users - each of these can have tens of thousands of elements so even operations
 with linear complexity, if heavy enough (with I/O or complex processing),
 can produce noticeable GUI freezing or stuttering. When you don't see a way
-to reduce algorithmic complexity, embed occasional `processEvents()` invocations
-in heavy loops (see `Connection::saveState()` to get the idea).
+to reduce algorithmic complexity, either split processing into isolated
+pieces that can be individually scheduled as queued events (see the end of
+`Connection::consumeRoomData()` to get the idea) or uncouple the logic from
+GUI and execute it outside of the main thread with `QtConcurrent` facilities.
 
 Having said that, there's always a trade-off between various attributes;
 in particular, readability and maintainability of the code is more important
@@ -323,14 +331,13 @@ that might not give the benefits you think it would.
 Speaking of profiling logs (see README.md on how to turn them on) - if you
 expect some code to take considerable (more than 10k "simple operations") time
 you might want to setup a `QElapsedTimer` and drop the elapsed time into logs
-under `PROFILER` logging category (see the existing code for examples -
-`room.cpp` has quite a few). In order to reduce small timespan logging spam,
-`PROFILER` log lines are usually guarded by a check that the timer counted
-some considerable time (200 microseconds by default, 20 microseconds for
-tighter parts). It's possible to override this limit library-wide by passing
-the new value (in microseconds) in `PROFILER_LOG_USECS` definition to
-the compiler; I don't think anybody ever used this facility. If you used it,
-and are reading this text - let me (`@kitsune`) know.
+under `PROFILER` logging category. See the existing code for examples -
+`room.cpp` has quite a few. In order to reduce small timespan logging spam,
+`PROFILER` log lines are usually guarded by a check that the timer counted big
+enough time (200 microseconds by default, 20 microseconds for tighter parts);
+this threshold can be altered at compile-time by defining `PROFILER_LOG_USECS`
+preprocessor symbol (i.e. passing `-DPROFILE_LOG_USECS=<usecs>` to the compiler
+if you're on Linux/macOS).
 
 ### Generated C++ code for CS API
 The code in `lib/csapi`, `lib/identity` and `lib/application-service`, although
@@ -338,9 +345,9 @@ it resides in Git, is actually generated from the official Swagger/OpenAPI
 definition files. If you're unhappy with something in there and want to improve
 the code, you have to understand the way these files are produced and setup
 some additional tooling. The shortest possible procedure resembling
-the below text can be found in .travis.yml (our CI configuration actually
-regenerates those files upon every build). As described below, there is also
-a handy build target for CMake.
+the below text can be found in .github/workflows/ci.yml (our CI configuration
+tests regeneration of those files). As described below, there is also a handy
+build target for CMake.
 
 #### Why generate the code at all?
 Because otherwise we have to do monkey business of writing boilerplate code,
@@ -353,63 +360,71 @@ found in [this talk about API description languages](https://youtu.be/W5TmRozH-r
 that also briefly touches on GTAD.
 
 #### Prerequisites for CS API code generation
-1. Get the source code of GTAD and its dependencies, e.g. using the command:
-   `git clone --recursive https://github.com/KitsuneRal/gtad.git`
-2. Build GTAD: in the source code directory, do `cmake . && cmake --build .`
-   (you might need to pass `-DCMAKE_PREFIX_PATH=<path to Qt>`,
-   similar to libQuotient itself).
-3. Get the Matrix CS API definitions that are included in a matrix-doc repo.
-   You can `git clone https://github.com/matrix-org/matrix-doc.git`,
-   the official repo; it's recommended though to instead
-   `git clone https://github.com/quotient-im/matrix-doc.git` - this repo closely
-   follows the official one, with an additional guarantee that you can always
-   generate working Quotient code from its HEAD commit. And of course you
-   can use your own repository if you need to change the API definition.
-4. If you plan to submit a PR or just would like the generated code to be
-   properly formatted, you should either ensure you have clang-format
-   (version 6 at least) in your PATH or pass the _absolute_ path to it by adding
-   `-DCLANG_FORMAT=<absolute path>` to the CMake invocation below.
+1. Get the source code of GTAD and its dependencies. Recent libQuotient
+   includes GTAD as a submodule so you can get everything you need by updating
+   gtad/gtad submodule in libQuotient sources:
+   `git submodule update --init --recursive gtad/gtad`.
+
+   You can also just clone GTAD sources to keep them separate from libQuotient:
+   `git clone --recursive https://github.com/quotient-im/gtad.git`
+2. Configure and build GTAD: same as libQuotient, it uses CMake so this should
+   be quite straightforward (if not - you're probably not quite ready for this
+   stuff anyway).
+3. Get Matrix CS API definitions from a matrix-spec repo. Although the official
+   repo is at https://github.com/matrix-org/matrix-spec.git` (formerly
+   https://github.com/matrix-org/matrix-doc.git), you may or may not be able
+   to generate working code from it because the way it evolves is not
+   necessarily in line with libQuotient needs. For that reason, a soft fork
+   of the official definitions is kept at
+   https://github.com/quotient-im/matrix-spec.git that guarantees buildability
+   of the generated code. This repo closely follows the official one (but maybe
+   not its freshest commit), applying a few adjustments on top. And of course
+   you can use your own repository if you need to change the API definition.
+4. If you plan to submit a PR with the generated code to libQuotient or just
+   would like it to be properly formatted, you should either ensure you have
+   clang-format (version 10 at least) in your PATH or pass
+   `-DCLANG_FORMAT=<path>` to CMake, as mentioned in the next section.
 
 #### Generating CS API contents
 1. Pass additional configuration to CMake when configuring libQuotient:
-   `-DMATRIX_DOC_PATH=<path to matrix-doc repo> -DGTAD_PATH=<path to gtad binary (not the repo!)>`.
-   If everything's right, these two CMake variables will be mentioned in
-   CMake output and will trigger configuration of an additional build target,
-   see the next step.
-2. Generate the code: `cmake --build <your build dir> --target update-api`;
-   if you use CMake with GNU Make, you can just do `make update-api` instead.
-   Building this target will create (overwriting without warning) `.h` and `.cpp`
-   files in `lib/csapi`, `lib/identity`, `lib/application-service` for all
-   YAML files it can find in `matrix-doc/api/client-server` and other files
-   in `matrix-doc/api` these depend on.
-3. Re-run CMake so that the build system knows about new files, if there are any
-   (this step is unnecessary if you use CMake 3.12 or later).
+   `-DMATRIX_SPEC_PATH=/path/to/matrix-spec/ -DGTAD_PATH=/path/to/gtad`.
+   Note that `MATRIX_SPEC_PATH` should lead to the repo while `GTAD_PATH` should
+   have the path to GTAD binary. If you need to specify where your clang-format
+   is (see the previous section) add `-DCLANG_FORMAT=/path/to/clang-format` to
+   the line above. If everything's right, the detected locations will be
+   mentioned in CMake output and will trigger configuration of an additional
+   build target called `update-api`.
+2. Generate the code: `cmake --build <your build dir> --target update-api`.
+   Building this target will create (overwriting without warning) source files
+   in `lib/csapi`, `lib/identity`, `lib/application-service` for all YAML files
+   it can find in `/path/to/matrix-spec/data/api/client-server` and their
+   dependencies.
 
 #### Changing generated code
 See the more detailed description of what GTAD is and how it works in the documentation on GTAD in its source repo. Only parts specific for libQuotient are described here.
 
 GTAD uses the following three kinds of sources:
-1. OpenAPI files. Each file is treated as a separate source (if you worked with
-   swagger-codegen - you do _not_ need to have a single file for the whole API).
-2. A configuration file, in our case it's `gtad/gtad.yaml` - this one is common
-   for all OpenAPI files GTAD is invoked on.
+1. OpenAPI files. Each file is treated as a separate source (unlike
+   swagger-codegen, you do _not_ need to have a single file for the whole API).
+2. A configuration file, in Quotient case it's `gtad/gtad.yaml` - common for
+   all OpenAPI files GTAD is invoked on.
 3. Source code template files: `gtad/*.mustache` - are also common.
 
 The Mustache files have a templated (not in C++ sense) definition of a network
-job, deriving from BaseJob; if necessary, data structure definitions used
+job class derived from BaseJob; if necessary, data structure definitions used
 by this job are put before the job class. Bigger Mustache files look a bit
 hideous for a newcomer; and the only known highlighter that can handle
-the combination of Mustache (originally a web templating language) and C++ is
-provided in CLion IDE. Fortunately, all our Mustache files are reasonably
+the combination of Mustache (originally a web templating language) and C++ can
+be found in CLion IDE. Fortunately, all our Mustache files are reasonably
 concise and well-formatted these days.
 To simplify things some reusable Mustache blocks are defined in `gtad.yaml` -
-see its `mustache:` section. Adventurous souls that would like  to figure
+see its `mustache:` section. Adventurous souls that would like to figure
 what's going on in these files should speak up in the Quotient room -
 I (Kitsune) will be very glad to help you out.
 
 The types map in `gtad.yaml` is the central switchboard when it comes to matching OpenAPI types with C++ (and Qt) ones. It uses the following type attributes aside from pretty obvious "imports:":
 * `avoidCopy` - this attribute defines whether a const ref should be used instead of a value. For basic types like int this is obviously unnecessary; but compound types like `QVector` should rather be taken by reference when possible.
-* `moveOnly` - some types are not copyable at all and must be moved instead (an obvious example is anything "tainted" with a member of type `std::unique_ptr<>`). The template will use `T&&` instead of `T` or `const T&` to pass such types around.
+* `moveOnly` - some types are not copyable at all and must be moved instead (an obvious example is anything "tainted" with a member of type `std::unique_ptr<>`).
 * `useOmittable` - wrap types that have no value with "null" semantics (i.e. number types and custom-defined data structures) into a special `Omittable<>` template defined in `converters.h`, a drop-in upgrade over `std::optional`.
 * `omittedValue` - an alternative for `useOmittable`, just provide a value used for an omitted parameter. This is used for bool parameters which normally are considered false if omitted (or they have an explicit default value, passed in the "official" GTAD's `defaultValue` variable).
 * `initializer` - this is a _partial_ (see GTAD and Mustache documentation for explanations but basically it's a variable that is a Mustache template itself) that specifies how exactly a default value should be passed to the parameter. E.g., the default value for a `QString` parameter is enclosed into `QStringLiteral`.
@@ -424,11 +439,12 @@ your commit into it (with an explanation what it is about and why).
 
 ### Standard checks
 
-The following warnings configuration is applied with GCC and Clang when using CMake:
-`-W -Wall -Wextra -pedantic -Werror=return-type -Wno-unused-parameter -Wno-gnu-zero-variadic-macro-arguments`
-(the last one is to mute a warning triggered by Qt code for debug logging).
-We don't turn most of the warnings to errors but please treat them as such.
-If you use Qt Creator, the following line can be used with the Clang code model:
+The warnings configuration applied when using CMake can be found in
+`CMakeLists.txt`. Most warnings triggered by that configuration are not formally
+considered errors (the compiler will keep going) but please treat them as such.
+If you want to be cautious, you can use the following line for your IDE's Clang
+analyzer code model to enable as many compiler warnings as reasonable (that
+does not include `clang-tidy`/`clazy` warnings - see below on those):
 `-Weverything -Werror=return-type -Wno-c++98-compat -Wno-c++98-compat-pedantic -Wno-unused-macros -Wno-newline-eof -Wno-exit-time-destructors -Wno-global-constructors -Wno-gnu-zero-variadic-macro-arguments -Wno-documentation -Wno-missing-prototypes -Wno-shadow-field-in-constructor -Wno-padded -Wno-weak-vtables -Wno-unknown-attributes -Wno-comma -Wno-string-conversion -Wno-return-std-move-in-c++11`.
 
 ### Continuous Integration
@@ -439,26 +455,16 @@ see the traffic lights from them on the PR page. If your PR fails
 on any platform double-check that it's not your code causing it - and fix
 (or ask how to fix if you don't know) if it is.
 
-### clang-format
-
-We strongly recommend using clang-format (version 10 or newer) or, even better,
-use an IDE that supports it. This will lay over a tedious task of following
-the assumed code style from your shoulders (and fingers) to your computer.
-
 ### Other tools
 
 Recent versions of Qt Creator and CLion can automatically run your code through
-clang-tidy. The following list of clang-tidy checks gives a good insight
-without too many false positives:
-`-*,bugprone-argument-comment,bugprone-assert-side-effect,bugprone-bool-pointer-implicit-conversion,bugprone-copy-constructor-init,bugprone-dangling-handle,bugprone-fold-init-type,bugprone-forward-declaration-namespace,bugprone-forwarding-reference-overload,bugprone-inaccurate-erase,bugprone-integer-division,bugprone-lambda-function-name,bugprone-macro-*,bugprone-move-forwarding-reference,bugprone-multiple-statement-macro,bugprone-parent-virtual-call,bugprone-signed-char-misuse,bugprone-sizeof-*,bugprone-string-constructor,bugprone-string-integer-assignment,bugprone-suspicious-*,bugprone-terminating-continue,bugprone-undefined-memory-manipulation,bugprone-undelegated-constructor,bugprone-unused-*,bugprone-use-after-move,bugprone-virtual-near-miss,cert-dcl03-c,cert-dcl21-cpp,cert-dcl50-cpp,cert-dcl54-cpp,cert-dcl58-cpp,cert-env33-c,cert-err09-cpp,cert-err34-c,cert-err52-cpp,cert-err60-cpp,cert-err61-cpp,cert-fio38-c,cert-flp30-c,cert-msc30-c,cert-msc50-cpp,cert-oop11-cpp,clang-analyzer-apiModeling.StdCLibraryFunctions,clang-analyzer-core.CallAndMessage,clang-analyzer-core.NullDereference,clang-analyzer-cplusplus.*,clang-analyzer-optin.cplusplus.*,cppcoreguidelines-c-copy-assignment-signature,cppcoreguidelines-non-private-member-variables-in-classes,cppcoreguidelines-pro-type-cstyle-cast,cppcoreguidelines-slicing,hicpp-deprecated-headers,hicpp-invalid-access-moved,hicpp-member-init,hicpp-move-const-arg,hicpp-new-delete-operators,hicpp-static-assert,hicpp-undelegated-constructor,hicpp-use-*,misc-*,-misc-definitions-in-headers,-misc-no-recursion,-misc-non-private-member-variables-in-classes,modernize-loop-convert,modernize-pass-by-value,modernize-return-braced-init-list,modernize-shrink-to-fit,modernize-unary-static-assert,modernize-use-*,-modernize-use-trailing-return-type,performance-*,-performance-no-automatic-move,-performance-noexcept-move-constructor,-performance-unnecessary-*,readability-*,-readability-braces-around-statements,-readability-implicit-bool-conversion,-readability-isolate-declaration,-readability-magic-numbers,-readability-named-parameter,-readability-qualified-auto`.
-
-Qt Creator, in addition, knows about clazy, an even deeper Qt-aware static
-analysis tool that produces some notices about Qt-specific issues that are
-easy to overlook otherwise, such as possible unintended copying of
-a Qt container, or unguarded null pointers. You can use this time to time
-(see Analyze menu in Qt Creator) instead of hogging your machine with
-deep analysis as you type (or after each saving, depending on your version
-of Qt Creator). Most of clazy checks are relevant to our code, except:
+clang-tidy. The source code contains `.clang-tidy` file with the recommended
+set of checks that doesn't give too many false positives.
+
+Qt Creator in addition knows about clazy, a Qt-aware static analysis tool that
+hunts for Qt-specific issues that are easy to overlook otherwise, such as
+possible unintended copying of a Qt container. Most of clazy checks are relevant
+to our code, except:
 `fully-qualified-moc-types,overloaded-signal,qstring-comparison-to-implicit-char,foreach,non-pod-global-static,qstring-allocations,jni-signatures,qt4-qstring-from-array`.
 
 ### Submitting API changes
@@ -466,7 +472,7 @@ of Qt Creator). Most of clazy checks are relevant to our code, except:
 If you changed the API definitions, the path to upstream becomes somewhat
 intricate, as you have to coordinate with two projects, making up to 4 PRs along
 the way. The recommended sequence depends on whether or not you have to
-[write an Matrix Spec Change aka MSC](https://matrix.org/docs/spec/proposals).
+[write a Matrix Spec Change aka MSC](https://matrix.org/docs/spec/proposals).
 Usually you have to, unless your API changes keep API semantics intact.
 In that case:
 1. Submit an MSC before submitting changes to the API definition files and
@@ -475,22 +481,22 @@ In that case:
    but it's necessary for the Matrix ecosystem integrity.
 3. When your MSC has at least some approvals (not necessarily a complete
    acceptance but at least some approvals should be there) submit a PR to
-   libQuotient, referring to your `matrix-doc` repo. Make sure that generated
+   libQuotient, referring to your `matrix-spec` repo. Make sure that generated
    files are committed separately from non-generated ones (no need to make two
    PRs; just separate them in different commits).
-4. If your libQuotient PR is approved and MSC is not there yet you'll be asked
-   to submit a PR with API definition files at
-   `https://github.com/quotient-im/matrix-doc`. Note that this is _not_
+4. If/when your libQuotient PR is approved and MSC is not there yet you'll
+   be asked to submit a PR with API definition files at
+   `https://github.com/quotient-im/matrix-spec`. Note that this is _not_
    an official repo; but you can refer to your libQuotient PR as
    an _implementation_ of the MSC - a necessary step before making a so-called
    "spec PR".
-5. Once MSC is accepted, submit your `matrix-doc` changes as a PR to
-   `https://github.com/matrix-org/matrix-doc` (the "spec PR" mentioned above).
+5. Once MSC is accepted, submit your `matrix-spec` changes as a PR to
+   `https://github.com/matrix-org/matrix-spec` (the "spec PR" mentioned above).
    This will require that your submission meets the standards set by this
    project (they are quite reasonable and not too hard to meet).
 
 If your changes don't need an MSC, it becomes a more straightforward combination
-of 2 PRs: one to `https://github.com/matrix-org/matrix-doc` ("spec PR") and one
+of 2 PRs: one to `https://github.com/matrix-org/matrix-spec` ("spec PR") and one
 to libQuotient (with the same guidance about putting generated and non-generated
 files in different commits).
 
@@ -512,26 +518,23 @@ When writing git commit messages, try to follow the guidelines in
 
 C++ is unfortunately not very coherent about SDK/package management, and we try to keep building the library as easy as possible. Because of that we are very conservative about adding dependencies to libQuotient. That relates to additional Qt components and even more to other libraries. Fortunately, even the Qt components now in use (Qt Core and Network) are very feature-rich and provide plenty of ready-made stuff.
 
-Regardless of the above paragraph (and as mentioned earlier in the text), we're now looking at possible options for futures and automated testing, so PRs onboarding those will be considered with much gratitude.
-
 Some cases need additional explanation:
 * Before rolling out your own super-optimised container or algorithm written
   from scratch, take a good long look through documentation on Qt and
   C++ standard library. Please try to reuse the existing facilities
   as much as possible.
-* You should have a good reason (or better several ones) to add a component
-  from KDE Frameworks. We don't rule this out and there's no prejudice against
-  KDE; it just so happened that KDE Frameworks is one of most obvious
-  reuse candidates but so far none of these components survived
-  as libQuotient deps. So we are cautious. Extra notice to KDE folks:
-  I'll be happy if an addon library on top of libQuotient is made using
-  KDE facilities, and I'm willing to take part in its evolution; but please
-  also respect LXDE people who normally don't have KDE frameworks installed.
+* libQuotient is a library to build Qt applications; for that reason,
+  components from KDE Frameworks should be really lightweight and useful
+  to be accepted as a dependency. If the intention is to better integrate
+  libQuotient into KDE environment there's nothing wrong in building another
+  library on top of libQuotient. Consider people who run LXDE and normally
+  don't have KDE frameworks installed (some even oppose installing those) -
+  libQuotient caters to them too.
 * Never forget that libQuotient is aimed to be a non-visual library;
   QtGui in dependencies is only driven by (entirely offscreen) dealing with
   QImages. While there's a bunch of visual code (in C++ and QML) shared
   between Quotient-enabled _applications_, this is likely to end up
-  in a separate (Quotient-enabled) library, rather than libQuotient itself.
+  in a separate (Quotient-backed) library, rather than libQuotient itself.
 
 ## Attribution
 
diff --git a/README.md b/README.md
index 71f2d04c..8be38b5c 100644
--- a/README.md
+++ b/README.md
@@ -7,8 +7,10 @@
 [![release](https://img.shields.io/github/release/quotient-im/libQuotient/all.svg)](https://github.com/quotient-im/libQuotient/releases/latest)
 [![](https://img.shields.io/cii/percentage/1023.svg?label=CII%20best%20practices)](https://bestpractices.coreinfrastructure.org/projects/1023/badge)
 ![](https://img.shields.io/github/commit-activity/y/quotient-im/libQuotient.svg)
-[![Language grade: C/C++](https://img.shields.io/lgtm/grade/cpp/g/quotient-im/libQuotient.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/quotient-im/libQuotient/context:cpp)
-[![merge-chance-badge](https://img.shields.io/endpoint?url=https%3A%2F%2Fmerge-chance.info%2Fbadge%3Frepo%3Dquotient-im/libquotient)](https://merge-chance.info/target?repo=quotient-im/libquotient)
+![CI Status](https://img.shields.io/github/workflow/status/quotient-im/libQuotient/CI)
+![Sonar Tech Debt](https://img.shields.io/sonar/tech_debt/quotient-im_libQuotient?server=https%3A%2F%2Fsonarcloud.io)
+![Sonar Coverage](https://img.shields.io/sonar/coverage/quotient-im_libQuotient?server=https%3A%2F%2Fsonarcloud.io)
+![Matrix](https://img.shields.io/matrix/quotient:matrix.org?logo=matrix)
 
 The Quotient project aims to produce a Qt5-based SDK to develop applications
 for [Matrix](https://matrix.org). libQuotient is a library that enables client
@@ -27,23 +29,21 @@ If you find what looks like a security issue, please use instructions
 in SECURITY.md.
 
 ## Getting and using libQuotient
-Depending on your platform, the library can come as a separate package.
-Recent releases of Debian and openSUSE, e.g., already have the package
-(under the old name). If your Linux repo doesn't provide binary package
-(either libqmatrixclient - older - or libquotient - newer), or you're
-on Windows or macOS, your best bet is to build the library from the source
-and bundle it with your application.
+Depending on your platform, the library can be obtained from a package
+management system. Recent releases of Debian and openSUSE, e.g., already have
+it. Alternatively, just build the library from the source and bundle it with
+your application, as described below.
 
 ### Pre-requisites
 - A recent Linux, macOS or Windows system (desktop versions are known to work;
   mobile operating systems where Qt is available might work too)
-  - Recent enough Linux examples: Debian Bullseye; Fedora 33; openSUSE Leap 15.3;
-    Ubuntu Focal Fossa.
-- Qt 5 (either Open Source or Commercial), 5.12 or higher
+  - Recent enough Linux examples: Debian Bullseye; Fedora 35;
+    openSUSE Leap 15.4; Ubuntu 22.04 LTS.
+- Qt 5 (either Open Source or Commercial), 5.15 or higher
 - CMake 3.16 or newer (from your package management system or
   [the official website](https://cmake.org/download/))
-- A C++ toolchain with complete (as much as possible) C++17 and basic C++20:
-  - GCC 10 (Windows, Linux, macOS), Clang 11 (Linux), Apple Clang 12 (macOS)
+- A C++ toolchain with that supports at least some subset of C++20:
+  - GCC 11 (Windows, Linux, macOS), Clang 11 (Linux), Apple Clang 12 (macOS)
     and Visual Studio 2019 (Windows) are the oldest officially supported.
 - Any build system that works with CMake should be fine:
   GNU Make and ninja on any platform, NMake and jom on Windows are known to work.
@@ -144,7 +144,7 @@ the standard variables coming with CMake. On top of them, Quotient introduces:
   Quotient and Quotient-dependent (if it uses `find_package(Quotient 0.6)`)
   code; so you can use `#ifdef Quotient_E2EE_ENABLED` to guard the code using
   E2EE parts of Quotient.
-- `MATRIX_DOC_PATH` and `GTAD_PATH` - these two variables are used to point
+- `MATRIX_SPEC_PATH` and `GTAD_PATH` - these two variables are used to point
   CMake to the directory with the matrix-doc repository containing API files
   and to a GTAD binary. These two are used to generate C++ files from Matrix
   Client-Server API description made in OpenAPI notation. This is not needed
@@ -165,14 +165,37 @@ by setting `Quotient_INSTALL_TESTS` to `OFF`.
 
 #### Building fails
 
-If `cmake` fails with...
-```
-CMake Warning at CMakeLists.txt:11 (find_package):
-  By not providing "FindQt5Widgets.cmake" in CMAKE_MODULE_PATH this project
-  has asked CMake to find a package configuration file provided by
-  "Qt5Widgets", but CMake did not find one.
-```
-...then you need to set the right `-DCMAKE_PREFIX_PATH` variable, see above.
+- If `cmake` fails with
+  ```
+  CMake Warning at CMakeLists.txt:11 (find_package):
+    By not providing "FindQt5Widgets.cmake" in CMAKE_MODULE_PATH this project
+    has asked CMake to find a package configuration file provided by
+    "Qt5Widgets", but CMake did not find one.
+  ```
+  then you need to set the right `-DCMAKE_PREFIX_PATH` variable, see above.
+
+- If you use GCC and get an "unknown declarator" compilation error in the file
+`qtconcurrentthreadengine.h` - unfortunately, it is an actual error in Qt 5.15
+sources, see https://bugreports.qt.io/browse/QTBUG-90568 (or
+https://bugreports.qt.io/browse/QTBUG-91909). The Qt company did not make
+an open source release with the fix, therefore:
+
+  - if you're on Linux - try to use Qt from your package management system, as
+    most likely this bug is already fixed in the packages
+  - if you're on Windows, or if you have to use Qt (5.15) from download.qt.io
+    for any other reason, you should apply the fix to Qt sources: locate
+    the file (the GCC error message tells exactly where it is), find the line
+    with the (strange-looking) `ThreadEngineStarter` constructor definition:
+    ```cplusplus
+    ThreadEngineStarter<void>(ThreadEngine<void> \*_threadEngine)
+    ```
+    and remove the template specialisation from the constructor name so that it
+    looks like
+    ```cplusplus
+    ThreadEngineStarter(ThreadEngine<void> \*_threadEngine)
+    ```
+    This will fix your build (and any other build involving QtConcurrent from
+    this installation of Qt - the fix is not specific to Quotient in any way).
 
 #### Logging configuration
 
diff --git a/.ci/adjust-config.sh b/autotests/adjust-config.sh
index b2ca52b2..68ea58ab 100755..100644
--- a/.ci/adjust-config.sh
+++ b/autotests/adjust-config.sh
@@ -3,9 +3,9 @@
 CMD=""
 
 $CMD perl -pi -w -e \
-    's/rc_messages_per_second.*/rc_messages_per_second: 1000/g;' data/homeserver.yaml
+    's/rc_messages_per_second.*/rc_messages_per_second: 1000/g;' homeserver.yaml
 $CMD perl -pi -w -e \
-    's/rc_message_burst_count.*/rc_message_burst_count: 10000/g;' data/homeserver.yaml
+    's/rc_message_burst_count.*/rc_message_burst_count: 10000/g;' homeserver.yaml
 
 (
 cat <<HEREDOC
@@ -36,18 +36,20 @@ rc_joins:
     per_second: 10000
     burst_count: 100000
 HEREDOC
-) | $CMD tee -a data/homeserver.yaml
+) | $CMD tee -a homeserver.yaml
 
 $CMD perl -pi -w -e \
-    's/#enable_registration: false/enable_registration: true/g;' data/homeserver.yaml
+    's/^#enable_registration: false/enable_registration: true/g;' homeserver.yaml
 $CMD perl -pi -w -e \
-    's/tls: false/tls: true/g;' data/homeserver.yaml
+    's/^#enable_registration_without_verification: .+/enable_registration_without_verification: true/g;' homeserver.yaml
 $CMD perl -pi -w -e \
-    's/#tls_certificate_path:/tls_certificate_path:/g;' data/homeserver.yaml
+    's/tls: false/tls: true/g;' homeserver.yaml
 $CMD perl -pi -w -e \
-    's/#tls_private_key_path:/tls_private_key_path:/g;' data/homeserver.yaml
+    's/#tls_certificate_path:/tls_certificate_path:/g;' homeserver.yaml
+$CMD perl -pi -w -e \
+    's/#tls_private_key_path:/tls_private_key_path:/g;' homeserver.yaml
 
-$CMD openssl req -x509 -newkey rsa:4096 -keyout data/localhost.tls.key -out data/localhost.tls.crt -days 365 -subj '/CN=localhost' -nodes
+$CMD openssl req -x509 -newkey rsa:4096 -keyout localhost.tls.key -out localhost.tls.crt -days 365 -subj '/CN=localhost' -nodes
 
-$CMD chmod 0777 data/localhost.tls.crt
-$CMD chmod 0777 data/localhost.tls.key
+$CMD chmod 0777 localhost.tls.crt
+$CMD chmod 0777 localhost.tls.key
diff --git a/autotests/run-tests.sh b/autotests/run-tests.sh
index 0d58e460..e7a228ef 100755
--- a/autotests/run-tests.sh
+++ b/autotests/run-tests.sh
@@ -1,34 +1,32 @@
 mkdir -p data
 chmod 0777 data
+
+SYNAPSE_IMAGE='matrixdotorg/synapse:v1.61.1'
+
 rm ~/.local/share/testolmaccount -rf
 docker run -v `pwd`/data:/data --rm \
-    -e SYNAPSE_SERVER_NAME=localhost -e SYNAPSE_REPORT_STATS=no matrixdotorg/synapse:v1.24.0 generate
-./.ci/adjust-config.sh
+    -e SYNAPSE_SERVER_NAME=localhost -e SYNAPSE_REPORT_STATS=no $SYNAPSE_IMAGE generate
+(cd data && . ../autotests/adjust-config.sh)
 docker run -d \
     --name synapse \
     -p 1234:8008 \
     -p 8448:8008 \
     -p 8008:8008 \
-    -v `pwd`/data:/data matrixdotorg/synapse:v1.24.0
+    -v `pwd`/data:/data $SYNAPSE_IMAGE
 trap "rm -rf ./data/*; docker rm -f synapse 2>&1 >/dev/null; trap - EXIT" EXIT
 
 echo Waiting for synapse to start...
 until curl -s -f -k https://localhost:1234/_matrix/client/versions; do echo "Checking ..."; sleep 2; done
 echo Register alice
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice1 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice2 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice3 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice4 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice5 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice6 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice7 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice8 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u alice9 -p secret -c /data/homeserver.yaml https://localhost:8008'
+for i in 1 2 3 4 5 6 7 8 9; do
+    docker exec synapse /bin/sh -c "register_new_matrix_user --admin -u alice$i -p secret -c /data/homeserver.yaml https://localhost:8008"
+done
 echo Register bob
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u bob1 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u bob2 -p secret -c /data/homeserver.yaml https://localhost:8008'
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u bob3 -p secret -c /data/homeserver.yaml https://localhost:8008'
+for i in 1 2 3; do
+    docker exec synapse /bin/sh -c "register_new_matrix_user --admin -u bob$i -p secret -c /data/homeserver.yaml https://localhost:8008"
+done
 echo Register carl
-docker exec synapse /bin/sh -c 'register_new_matrix_user --admin -u carl -p secret -c /data/homeserver.yaml https://localhost:8008'
+docker exec synapse /bin/sh -c "register_new_matrix_user --admin -u carl -p secret -c /data/homeserver.yaml https://localhost:8008"
 
 GTEST_COLOR=1 ctest --verbose "$@"
+
diff --git a/autotests/testfilecrypto.cpp b/autotests/testfilecrypto.cpp
index e6bec1fe..29521060 100644
--- a/autotests/testfilecrypto.cpp
+++ b/autotests/testfilecrypto.cpp
@@ -3,15 +3,20 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
 
 #include "testfilecrypto.h"
-#include "events/encryptedfile.h"
+
+#include "events/filesourceinfo.h"
+
 #include <qtest.h>
 
 using namespace Quotient;
 void TestFileCrypto::encryptDecryptData()
 {
     QByteArray data = "ABCDEF";
-    auto [file, cipherText] = EncryptedFile::encryptFile(data);
-    auto decrypted = file.decryptFile(cipherText);
-    QCOMPARE(data, decrypted);
+    auto [file, cipherText] = encryptFile(data);
+    auto decrypted = decryptFile(cipherText, file);
+    // AES CTR produces ciphertext of the same size as the original
+    QCOMPARE(cipherText.size(), data.size());
+    QCOMPARE(decrypted.size(), data.size());
+    QCOMPARE(decrypted, data);
 }
 QTEST_APPLESS_MAIN(TestFileCrypto)
diff --git a/autotests/testgroupsession.cpp b/autotests/testgroupsession.cpp
index 2566669e..3c329a8a 100644
--- a/autotests/testgroupsession.cpp
+++ b/autotests/testgroupsession.cpp
@@ -16,11 +16,11 @@ void TestGroupSession::groupSessionPicklingValid()
     QVERIFY(QByteArray::fromBase64(ogsId).size() > 0);
     QCOMPARE(0, ogs->sessionMessageIndex());
 
-    auto ogsPickled = std::get<QByteArray>(ogs->pickle(Unencrypted {}));
-    auto ogs2 = std::get<QOlmOutboundGroupSessionPtr>(QOlmOutboundGroupSession::unpickle(ogsPickled, Unencrypted {}));
+    auto ogsPickled = ogs->pickle(Unencrypted {}).value();
+    auto ogs2 = QOlmOutboundGroupSession::unpickle(ogsPickled, Unencrypted {}).value();
     QCOMPARE(ogsId, ogs2->sessionId());
 
-    auto igs = QOlmInboundGroupSession::create(std::get<QByteArray>(ogs->sessionKey()));
+    auto igs = QOlmInboundGroupSession::create(ogs->sessionKey().value());
     const auto igsId = igs->sessionId();
     // ID is valid base64?
     QVERIFY(QByteArray::fromBase64(igsId).size() > 0);
@@ -29,22 +29,22 @@ void TestGroupSession::groupSessionPicklingValid()
     QCOMPARE(0, igs->firstKnownIndex());
 
     auto igsPickled = igs->pickle(Unencrypted {});
-    igs = std::get<QOlmInboundGroupSessionPtr>(QOlmInboundGroupSession::unpickle(igsPickled, Unencrypted {}));
+    igs = QOlmInboundGroupSession::unpickle(igsPickled, Unencrypted {}).value();
     QCOMPARE(igsId, igs->sessionId());
 }
 
 void TestGroupSession::groupSessionCryptoValid()
 {
     auto ogs = QOlmOutboundGroupSession::create();
-    auto igs = QOlmInboundGroupSession::create(std::get<QByteArray>(ogs->sessionKey()));
+    auto igs = QOlmInboundGroupSession::create(ogs->sessionKey().value());
     QCOMPARE(ogs->sessionId(), igs->sessionId());
 
     const auto plainText = QStringLiteral("Hello world!");
-    const auto ciphertext = std::get<QByteArray>(ogs->encrypt(plainText));
+    const auto ciphertext = ogs->encrypt(plainText).value();
     // ciphertext valid base64?
     QVERIFY(QByteArray::fromBase64(ciphertext).size() > 0);
 
-    const auto decryptionResult = std::get<std::pair<QString, uint32_t>>(igs->decrypt(ciphertext));
+    const auto decryptionResult = igs->decrypt(ciphertext).value();
 
     //// correct plaintext?
     QCOMPARE(plainText, decryptionResult.first);
diff --git a/autotests/testolmaccount.cpp b/autotests/testolmaccount.cpp
index 9989665a..4b32393d 100644
--- a/autotests/testolmaccount.cpp
+++ b/autotests/testolmaccount.cpp
@@ -10,7 +10,7 @@
 #include <e2ee/qolmaccount.h>
 #include <e2ee/qolmutility.h>
 #include <events/encryptionevent.h>
-#include <events/encryptedfile.h>
+#include <events/filesourceinfo.h>
 #include <networkaccessmanager.h>
 #include <room.h>
 
@@ -21,7 +21,7 @@ void TestOlmAccount::pickleUnpickledTest()
     QOlmAccount olmAccount(QStringLiteral("@foo:bar.com"), QStringLiteral("QuotientTestDevice"));
     olmAccount.createNewAccount();
     auto identityKeys = olmAccount.identityKeys();
-    auto pickled = std::get<QByteArray>(olmAccount.pickle(Unencrypted{}));
+    auto pickled = olmAccount.pickle(Unencrypted{}).value();
     QOlmAccount olmAccount2(QStringLiteral("@foo:bar.com"), QStringLiteral("QuotientTestDevice"));
     olmAccount2.unpickle(pickled, Unencrypted{});
     auto identityKeys2 = olmAccount2.identityKeys();
@@ -57,8 +57,7 @@ void TestOlmAccount::signatureValid()
     const auto identityKeys = olmAccount.identityKeys();
     const auto ed25519Key = identityKeys.ed25519;
     const auto verify = utility.ed25519Verify(ed25519Key, message, signature);
-    QVERIFY(std::holds_alternative<bool>(verify));
-    QVERIFY(std::get<bool>(verify) == true);
+    QVERIFY(verify.value_or(false));
 }
 
 void TestOlmAccount::oneTimeKeysValid()
@@ -157,8 +156,7 @@ void TestOlmAccount::encryptedFile()
         "sha256": "fdSLu/YkRx3Wyh3KQabP3rd6+SFiKg5lsJZQHtkSAYA"
       }})");
 
-    EncryptedFile file;
-    JsonObjectConverter<EncryptedFile>::fillFrom(doc.object(), file);
+    const auto file = fromJson<EncryptedFileMetadata>(doc);
 
     QCOMPARE(file.v, "v2");
     QCOMPARE(file.iv, "w+sE15fzSc0AAAAAAAAAAA");
@@ -199,13 +197,16 @@ void TestOlmAccount::uploadIdentityKey()
 
     QVERIFY(idKeys.curve25519.size() > 10);
 
-    OneTimeKeys unused;
+    UnsignedOneTimeKeys unused;
     auto request = olmAccount->createUploadKeyRequest(unused);
     connect(request, &BaseJob::result, this, [request, conn] {
-        QCOMPARE(request->oneTimeKeyCounts().size(), 0);
-    });
-    connect(request, &BaseJob::failure, this, [] {
-        QFAIL("upload failed");
+        if (!request->status().good())
+            QFAIL("upload failed");
+        const auto& oneTimeKeyCounts = request->oneTimeKeyCounts();
+        // Allow the response to have entries with zero counts
+        QCOMPARE(std::accumulate(oneTimeKeyCounts.begin(),
+                                 oneTimeKeyCounts.end(), 0),
+                 0);
     });
     conn->run(request);
     QSignalSpy spy3(request, &BaseJob::result);
@@ -222,19 +223,17 @@ void TestOlmAccount::uploadOneTimeKeys()
 
     auto oneTimeKeys = olmAccount->oneTimeKeys();
 
-    QHash<QString, QVariant> oneTimeKeysHash;
+    OneTimeKeys oneTimeKeysHash;
     const auto curve = oneTimeKeys.curve25519();
     for (const auto &[keyId, key] : asKeyValueRange(curve)) {
         oneTimeKeysHash["curve25519:"+keyId] = key;
     }
     auto request = new UploadKeysJob(none, oneTimeKeysHash);
     connect(request, &BaseJob::result, this, [request, conn] {
-        QCOMPARE(request->oneTimeKeyCounts().size(), 1);
+        if (!request->status().good())
+            QFAIL("upload failed");
         QCOMPARE(request->oneTimeKeyCounts().value(Curve25519Key), 5);
     });
-    connect(request, &BaseJob::failure, this, [] {
-        QFAIL("upload failed");
-    });
     conn->run(request);
     QSignalSpy spy3(request, &BaseJob::result);
     QVERIFY(spy3.wait(10000));
@@ -248,21 +247,17 @@ void TestOlmAccount::uploadSignedOneTimeKeys()
     QCOMPARE(nKeys, 5);
 
     auto oneTimeKeys = olmAccount->oneTimeKeys();
-    QHash<QString, QVariant> oneTimeKeysHash;
+    OneTimeKeys oneTimeKeysHash;
     const auto signedKey = olmAccount->signOneTimeKeys(oneTimeKeys);
     for (const auto &[keyId, key] : asKeyValueRange(signedKey)) {
-        QVariant var;
-        var.setValue(key);
-        oneTimeKeysHash[keyId] = var;
+        oneTimeKeysHash[keyId] = key;
     }
     auto request = new UploadKeysJob(none, oneTimeKeysHash);
     connect(request, &BaseJob::result, this, [request, nKeys, conn] {
-        QCOMPARE(request->oneTimeKeyCounts().size(), 1);
+        if (!request->status().good())
+            QFAIL("upload failed");
         QCOMPARE(request->oneTimeKeyCounts().value(SignedCurve25519Key), nKeys);
     });
-    connect(request, &BaseJob::failure, this, [] {
-        QFAIL("upload failed");
-    });
     conn->run(request);
     QSignalSpy spy3(request, &BaseJob::result);
     QVERIFY(spy3.wait(10000));
@@ -277,12 +272,10 @@ void TestOlmAccount::uploadKeys()
     auto otks = olmAccount->oneTimeKeys();
     auto request = olmAccount->createUploadKeyRequest(otks);
     connect(request, &BaseJob::result, this, [request, conn] {
-        QCOMPARE(request->oneTimeKeyCounts().size(), 1);
+        if (!request->status().good())
+            QFAIL("upload failed");
         QCOMPARE(request->oneTimeKeyCounts().value(SignedCurve25519Key), 1);
     });
-    connect(request, &BaseJob::failure, this, [] {
-        QFAIL("upload failed");
-    });
     conn->run(request);
     QSignalSpy spy3(request, &BaseJob::result);
     QVERIFY(spy3.wait(10000));
@@ -298,7 +291,6 @@ void TestOlmAccount::queryTest()
     aliceOlm->generateOneTimeKeys(1);
     auto aliceRes = aliceOlm->createUploadKeyRequest(aliceOlm->oneTimeKeys());
     connect(aliceRes, &BaseJob::result, this, [aliceRes] {
-        QCOMPARE(aliceRes->oneTimeKeyCounts().size(), 1);
         QCOMPARE(aliceRes->oneTimeKeyCounts().value(SignedCurve25519Key), 1);
     });
     QSignalSpy spy(aliceRes, &BaseJob::result);
@@ -309,7 +301,6 @@ void TestOlmAccount::queryTest()
     bobOlm->generateOneTimeKeys(1);
     auto bobRes = bobOlm->createUploadKeyRequest(aliceOlm->oneTimeKeys());
     connect(bobRes, &BaseJob::result, this, [bobRes] {
-        QCOMPARE(bobRes->oneTimeKeyCounts().size(), 1);
         QCOMPARE(bobRes->oneTimeKeyCounts().value(SignedCurve25519Key), 1);
     });
     QSignalSpy spy1(bobRes, &BaseJob::result);
@@ -369,7 +360,6 @@ void TestOlmAccount::claimKeys()
     auto request = bobOlm->createUploadKeyRequest(bobOlm->oneTimeKeys());
 
     connect(request, &BaseJob::result, this, [request, bob] {
-        QCOMPARE(request->oneTimeKeyCounts().size(), 1);
         QCOMPARE(request->oneTimeKeyCounts().value(SignedCurve25519Key), 1);
     });
     bob->run(request);
@@ -380,47 +370,47 @@ void TestOlmAccount::claimKeys()
     // Alice retrieves bob's keys & claims one signed one-time key.
     QHash<QString, QStringList> deviceKeys;
     deviceKeys[bob->userId()] = QStringList();
-    auto job = alice->callApi<QueryKeysJob>(deviceKeys);
-    connect(job, &BaseJob::result, this, [bob, alice, job, this] {
-        const auto& bobDevices = job->deviceKeys().value(bob->userId());
-        QVERIFY(!bobDevices.empty());
-
-        // Retrieve the identity key for the current device.
-        const auto& bobEd25519 =
-            bobDevices.value(bob->deviceId()).keys["ed25519:" + bob->deviceId()];
-
-        const auto currentDevice = bobDevices[bob->deviceId()];
-
-        // Verify signature.
-        QVERIFY(verifyIdentitySignature(currentDevice, bob->deviceId(),
-                                        bob->userId()));
-
-        QHash<QString, QHash<QString, QString>> oneTimeKeys;
-        oneTimeKeys[bob->userId()] = QHash<QString, QString>();
-        oneTimeKeys[bob->userId()][bob->deviceId()] = SignedCurve25519Key;
-
-        auto job = alice->callApi<ClaimKeysJob>(oneTimeKeys);
-        connect(job, &BaseJob::result, this, [bob, bobEd25519, job] {
-            const auto userId = bob->userId();
-            const auto deviceId = bob->deviceId();
-
-            // The device exists.
-            QCOMPARE(job->oneTimeKeys().size(), 1);
-            QCOMPARE(job->oneTimeKeys().value(userId).size(), 1);
-
-            // The key is the one bob sent.
-            const auto& oneTimeKey =
-                job->oneTimeKeys().value(userId).value(deviceId);
-            QVERIFY(oneTimeKey.canConvert<QVariantMap>());
-
-            const auto varMap = oneTimeKey.toMap();
-            QVERIFY(std::any_of(varMap.constKeyValueBegin(),
-                                varMap.constKeyValueEnd(), [](const auto& kv) {
-                                    return kv.first.startsWith(
-                                        SignedCurve25519Key);
-                                }));
-        });
+    auto queryKeysJob = alice->callApi<QueryKeysJob>(deviceKeys);
+    QSignalSpy requestSpy2(queryKeysJob, &BaseJob::result);
+    QVERIFY(requestSpy2.wait(10000));
+
+    const auto& bobDevices = queryKeysJob->deviceKeys().value(bob->userId());
+    QVERIFY(!bobDevices.empty());
+
+    const auto currentDevice = bobDevices[bob->deviceId()];
+
+    // Verify signature.
+    QVERIFY(verifyIdentitySignature(currentDevice, bob->deviceId(),
+                                    bob->userId()));
+    // Retrieve the identity key for the current device.
+    const auto& bobEd25519 =
+        bobDevices.value(bob->deviceId()).keys["ed25519:" + bob->deviceId()];
+
+    QHash<QString, QHash<QString, QString>> oneTimeKeys;
+    oneTimeKeys[bob->userId()] = QHash<QString, QString>();
+    oneTimeKeys[bob->userId()][bob->deviceId()] = SignedCurve25519Key;
+
+    auto claimKeysJob = alice->callApi<ClaimKeysJob>(oneTimeKeys);
+    connect(claimKeysJob, &BaseJob::result, this, [bob, bobEd25519, claimKeysJob] {
+        const auto userId = bob->userId();
+        const auto deviceId = bob->deviceId();
+
+        // The device exists.
+        QCOMPARE(claimKeysJob->oneTimeKeys().size(), 1);
+        QCOMPARE(claimKeysJob->oneTimeKeys().value(userId).size(), 1);
+
+        // The key is the one bob sent.
+        const auto& oneTimeKeys =
+            claimKeysJob->oneTimeKeys().value(userId).value(deviceId);
+        for (auto it = oneTimeKeys.begin(); it != oneTimeKeys.end(); ++it) {
+            if (it.key().startsWith(SignedCurve25519Key)
+                && std::holds_alternative<SignedOneTimeKey>(it.value()))
+                return;
+        }
+        QFAIL("The claimed one time key is not in /claim response");
     });
+    QSignalSpy completionSpy(claimKeysJob, &BaseJob::result);
+    QVERIFY(completionSpy.wait(10000));
 }
 
 void TestOlmAccount::claimMultipleKeys()
@@ -435,7 +425,6 @@ void TestOlmAccount::claimMultipleKeys()
     auto res = olm->createUploadKeyRequest(olm->oneTimeKeys());
     QSignalSpy spy(res, &BaseJob::result);
     connect(res, &BaseJob::result, this, [res] {
-        QCOMPARE(res->oneTimeKeyCounts().size(), 1);
         QCOMPARE(res->oneTimeKeyCounts().value(SignedCurve25519Key), 10);
     });
     alice->run(res);
@@ -446,7 +435,6 @@ void TestOlmAccount::claimMultipleKeys()
     auto res1 = olm1->createUploadKeyRequest(olm1->oneTimeKeys());
     QSignalSpy spy1(res1, &BaseJob::result);
     connect(res1, &BaseJob::result, this, [res1] {
-        QCOMPARE(res1->oneTimeKeyCounts().size(), 1);
         QCOMPARE(res1->oneTimeKeyCounts().value(SignedCurve25519Key), 10);
     });
     alice1->run(res1);
@@ -457,7 +445,6 @@ void TestOlmAccount::claimMultipleKeys()
     auto res2 = olm2->createUploadKeyRequest(olm2->oneTimeKeys());
     QSignalSpy spy2(res2, &BaseJob::result);
     connect(res2, &BaseJob::result, this, [res2] {
-        QCOMPARE(res2->oneTimeKeyCounts().size(), 1);
         QCOMPARE(res2->oneTimeKeyCounts().value(SignedCurve25519Key), 10);
     });
     alice2->run(res2);
@@ -481,7 +468,6 @@ void TestOlmAccount::claimMultipleKeys()
     QVERIFY(jobSpy.wait(10000));
     const auto userId = alice->userId();
 
-    QCOMPARE(job->oneTimeKeys().size(), 1);
     QCOMPARE(job->oneTimeKeys().value(userId).size(), 3);
 }
 
diff --git a/autotests/testolmsession.cpp b/autotests/testolmsession.cpp
index 5436c392..182659e7 100644
--- a/autotests/testolmsession.cpp
+++ b/autotests/testolmsession.cpp
@@ -20,8 +20,8 @@ std::pair<QOlmSessionPtr, QOlmSessionPtr> createSessionPair()
     const QByteArray oneTimeKeyA("WzsbsjD85iB1R32iWxfJdwkgmdz29ClMbJSJziECYwk");
     const QByteArray identityKeyB("q/YhJtog/5VHCAS9rM9uUf6AaFk1yPe4GYuyUOXyQCg");
     const QByteArray oneTimeKeyB("oWvzryma+B2onYjo3hM6A3Mgo/Yepm8HvgSvwZMTnjQ");
-    auto outbound = std::get<QOlmSessionPtr>(accountA
-        .createOutboundSession(identityKeyB, oneTimeKeyB));
+    auto outbound =
+        accountA.createOutboundSession(identityKeyB, oneTimeKeyB).value();
 
     const auto preKey = outbound->encrypt(""); // Payload does not matter for PreKey
 
@@ -29,7 +29,7 @@ std::pair<QOlmSessionPtr, QOlmSessionPtr> createSessionPair()
         // We can't call QFail here because it's an helper function returning a value
         throw "Wrong first message type received, can't create session";
     }
-    auto inbound = std::get<QOlmSessionPtr>(accountB.createInboundSession(preKey));
+    auto inbound = accountB.createInboundSession(preKey).value();
     return { std::move(inbound), std::move(outbound) };
 }
 
@@ -45,10 +45,10 @@ void TestOlmSession::olmEncryptDecrypt()
     const auto encrypted = outboundSession->encrypt("Hello world!");
     if (encrypted.type() == QOlmMessage::PreKey) {
         QOlmMessage m(encrypted); // clone
-        QVERIFY(std::get<bool>(inboundSession->matchesInboundSession(m)));
+        QVERIFY(inboundSession->matchesInboundSession(m));
     }
 
-    const auto decrypted = std::get<QString>(inboundSession->decrypt(encrypted));
+    const auto decrypted = inboundSession->decrypt(encrypted).value();
 
     QCOMPARE(decrypted, "Hello world!");
 }
@@ -56,11 +56,11 @@ void TestOlmSession::olmEncryptDecrypt()
 void TestOlmSession::correctSessionOrdering()
 {
     // n0W5IJ2ZmaI9FxKRj/wohUQ6WEU0SfoKsgKKHsr4VbM
-    auto session1 = std::get<QOlmSessionPtr>(QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UGvlaV6t/0ihD2/0QGckDIvbmE1aV+PxB0zUtHXh99bI/60N+PWkCLA84jEY4sz3d45ui/TVoFGLDHlymKxvlj7XngXrbtlxSkVntsPzDiNpKEXCa26N2ubKpQ0fbjrV5gbBTYWfU04DXHPXFDTksxpNALYt/h0eVMVhf6hB0ZzpLBsOG0mpwkLufwub0CuDEDGGmRddz3TcNCLq5NnI8R9udDWvHAkTS1UTbHuIf/y6cZg875nJyXpAvd8/XhL8TOo8ot2sE1fElBa4vrH/m9rBQMC1GPkhLBIizmY44C+Sq9PQRnF+uCZ", Unencrypted{}));
+    auto session1 = QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UGvlaV6t/0ihD2/0QGckDIvbmE1aV+PxB0zUtHXh99bI/60N+PWkCLA84jEY4sz3d45ui/TVoFGLDHlymKxvlj7XngXrbtlxSkVntsPzDiNpKEXCa26N2ubKpQ0fbjrV5gbBTYWfU04DXHPXFDTksxpNALYt/h0eVMVhf6hB0ZzpLBsOG0mpwkLufwub0CuDEDGGmRddz3TcNCLq5NnI8R9udDWvHAkTS1UTbHuIf/y6cZg875nJyXpAvd8/XhL8TOo8ot2sE1fElBa4vrH/m9rBQMC1GPkhLBIizmY44C+Sq9PQRnF+uCZ", Unencrypted{}).value();
     // +9pHJhP3K4E5/2m8PYBPLh8pS9CJodwUOh8yz3mnmw0
-    auto session2 = std::get<QOlmSessionPtr>(QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UFD+q37/WlfTAzQsSjCdD07FcErZ4siEy5vpiB+pyO8i53ptZvb2qRvqNKFzPaXuu33PS2PBTmmnR+kJt+DgDNqWadyaj/WqEAejc7ALqSs5GuhbZtpoLe+lRSRK0rwVX3gzz4qrl8pm0pD5pSZAUWRXDRlieGWMclz68VUvnSaQH7ElTo4S634CJk+xQfFFCD26v0yONPSN6rwouS1cWPuG5jTlnV8vCFVTU2+lduKh54Ko6FUJ/ei4xR8Nk2duBGSc/TdllX9e2lDYHSUkWoD4ti5xsFioB8Blus7JK9BZfcmRmdlxIOD", Unencrypted {}));
+    auto session2 = QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UFD+q37/WlfTAzQsSjCdD07FcErZ4siEy5vpiB+pyO8i53ptZvb2qRvqNKFzPaXuu33PS2PBTmmnR+kJt+DgDNqWadyaj/WqEAejc7ALqSs5GuhbZtpoLe+lRSRK0rwVX3gzz4qrl8pm0pD5pSZAUWRXDRlieGWMclz68VUvnSaQH7ElTo4S634CJk+xQfFFCD26v0yONPSN6rwouS1cWPuG5jTlnV8vCFVTU2+lduKh54Ko6FUJ/ei4xR8Nk2duBGSc/TdllX9e2lDYHSUkWoD4ti5xsFioB8Blus7JK9BZfcmRmdlxIOD", Unencrypted {}).value();
     // MC7n8hX1l7WlC2/WJGHZinMocgiBZa4vwGAOredb/ME
-    auto session3 = std::get<QOlmSessionPtr>(QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UGNk2TmVDJ95K0Nywf24FNklNVtXtFDiFPHFwNSmCbHNCp3hsGtZlt0AHUkMmL48XklLqzwtVk5/v2RRmSKR5LqYdIakrtuK/fY0ENhBZIbI1sRetaJ2KMbY9l6rCJNfFg8VhpZ4KTVvEZVuP9g/eZkCnP5NxzXiBRF6nfY3O/zhcKxa3acIqs6BMhyLsfuJ80t+hQ1HvVyuhBerGujdSDzV9tJ9SPidOwfYATk81LVF9hTmnI0KaZa7qCtFzhG0dU/Z3hIWH9HOaw1aSB/IPmughbwdJOwERyhuo3YHoznlQnJ7X252BlI", Unencrypted{}));
+    auto session3 = QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UGNk2TmVDJ95K0Nywf24FNklNVtXtFDiFPHFwNSmCbHNCp3hsGtZlt0AHUkMmL48XklLqzwtVk5/v2RRmSKR5LqYdIakrtuK/fY0ENhBZIbI1sRetaJ2KMbY9l6rCJNfFg8VhpZ4KTVvEZVuP9g/eZkCnP5NxzXiBRF6nfY3O/zhcKxa3acIqs6BMhyLsfuJ80t+hQ1HvVyuhBerGujdSDzV9tJ9SPidOwfYATk81LVF9hTmnI0KaZa7qCtFzhG0dU/Z3hIWH9HOaw1aSB/IPmughbwdJOwERyhuo3YHoznlQnJ7X252BlI", Unencrypted{}).value();
 
     const auto session1Id = session1->sessionId();
     const auto session2Id = session2->sessionId();
diff --git a/autotests/testolmutility.cpp b/autotests/testolmutility.cpp
index b4532c8d..5b67c805 100644
--- a/autotests/testolmutility.cpp
+++ b/autotests/testolmutility.cpp
@@ -6,6 +6,8 @@
 #include "e2ee/qolmaccount.h"
 #include "e2ee/qolmutility.h"
 
+#include <olm/olm.h>
+
 using namespace Quotient;
 
 void TestOlmUtility::canonicalJSON()
@@ -79,10 +81,13 @@ void TestOlmUtility::verifySignedOneTimeKey()
     delete[](reinterpret_cast<uint8_t *>(utility));
 
     QOlmUtility utility2;
-    auto res2 = std::get<bool>(utility2.ed25519Verify(aliceOlm.identityKeys().ed25519, msg, signatureBuf1));
+    auto res2 =
+        utility2
+            .ed25519Verify(aliceOlm.identityKeys().ed25519, msg, signatureBuf1)
+            .value_or(false);
 
     //QCOMPARE(std::string(olm_utility_last_error(utility)), "SUCCESS");
-    QCOMPARE(res2, true);
+    QVERIFY(res2);
 }
 
 void TestOlmUtility::validUploadKeysRequest()
diff --git a/gtad/gtad b/gtad/gtad
new file mode 160000
+Subproject 9ea32fb74767a62a3a0d27b3b181e8c18fb0c69
diff --git a/gtad/gtad.yaml b/gtad/gtad.yaml
index 03c23886..0bec3b7a 100644
--- a/gtad/gtad.yaml
+++ b/gtad/gtad.yaml
@@ -29,6 +29,8 @@ analyzer:
     login>/user: ""
     login>/medium: ""
     login>/address: ""
+    login</home_server: ""
+    register</home_server: ""
 
   # Structure inside `types`:
   # - swaggerType: <targetTypeSpec>
@@ -85,11 +87,11 @@ analyzer:
           imports: '"events/eventloader.h"'
         +on:
         - /state_event.yaml$/: StateEventPtr
-        - /room_event.yaml$/: RoomEventPtr
-        - /event.yaml$/: EventPtr
-      - /m\.room\.member/: void # Skip resolving; see EventsArray<> below
+        - /(room|client)_event.yaml$/: RoomEventPtr
+        - /event(_without_room_id)?.yaml$/: EventPtr
       - +set:
-          # This renderer actually applies to all $ref things
+          # This renderer applies to everything actually $ref'ed
+          # (not substituted)
           _importRenderer: '"{{#segments}}{{_}}{{#_join}}/{{/_join}}{{/segments}}.h"'
         +on:
         - '/^(\./)?definitions/request_email_validation.yaml$/':
@@ -97,38 +99,53 @@ analyzer:
         - '/^(\./)?definitions/request_msisdn_validation.yaml$/':
             title: MsisdnValidationData
         - /_filter.yaml$/: # Event/RoomEventFilters do NOT need Omittable<>
+
+          # Despite being used in two calls, it's more practical to have those
+          # fields available as getters right from the respective job classes
         - /public_rooms_response.yaml$/: { _inline: true }
+
+          # list_public_rooms.yaml (via public_rooms_response.yaml) and
+          # space_hierarchy.yaml use public_rooms_chunk.yaml as a common base
+          # structure, adding (space_hiearchy) or overriding
+          # (public_rooms_response) fields for their purposes. The spec text
+          # confusingly ends up with having two different structures named
+          # "PublicRoomsChunk". To make sure the types are distinct in
+          # libQuotient, this common base is inlined into the actually used
+          # data structures (that have distinct names) defined
+          # in space_hierarchy.h and public_rooms_response.h, respectively
+        - /public_rooms_chunk.yaml$/: { _inline: true }
         - //: *UseOmittable # Also apply "avoidCopy" to all other ref'ed types
     - schema:
       - getTurnServer<: *QJsonObject # It's used as an opaque JSON object
-      - PublicRoomResponse: { _inline: true }
 #      - defineFilter>: &Filter # Force folding into a structure
 #          type: Filter
 #          imports: '"csapi/definitions/sync_filter.h"'
 #      - getFilter<: *Filter
+      - StrippedChildStateEvent: void # only used in an array, see below
       - RoomFilter: # A structure inside Filter, same story as with *_filter.yaml
+      - OneTimeKeys:
+          type: OneTimeKeys
+          imports: '"e2ee/e2ee.h"'
       - //: *UseOmittable
     - array:
       - string: QStringList
       - +set: { moveOnly: }
         +on:
-        - /^Notification|Result$/:
-            type: "std::vector<{{1}}>"
+        - /^Notification|Result|ChildRoomsChunk$/: "std::vector<{{1}}>"
+        - StrippedChildStateEvent:
+            type: StateEvents
             imports: '"events/eventloader.h"'
-        - /m\.room\.member/: # Only used in an array (see also above)
-            type: "EventsArray<RoomMemberEvent>"
-            imports: '"events/roommemberevent.h"'
-        - /state_event.yaml$/: StateEvents
-        - /room_event.yaml$/: RoomEvents
-        - /event.yaml$/: Events
+        - /state_event.yaml$/: StateEvents # 'imports' already set under $ref
+        - /(room|client)_event.yaml$/: RoomEvents # ditto
+        - /event(_without_room_id)?.yaml$/: Events # ditto
       - //: "QVector<{{1}}>"
     - map: # `additionalProperties` in OpenAPI
       - RoomState:
           type: "UnorderedMap<QString, {{1}}>"
           moveOnly:
       - /.+/: "QHash<QString, {{1}}>"
-      - //: QVariantHash
-    - variant: # A sequence `type` (multitype) in OpenAPI
+      - //: QVariantHash # QJsonObject?..
+    - variant: # A sequence `type` or a 'oneOf' group in OpenAPI
       - /^string,null|null,string$/: *QString
       - //: QVariant
 
@@ -164,11 +181,8 @@ mustache:
     qualifiedMaybeOmittableType:
       "{{>openOmittable}}{{dataType.qualifiedName}}{{>closeOmittable}}"
 
-    ref: "{{#avoidCopy}}&{{/avoidCopy}}{{#moveOnly}}&&{{/moveOnly}}"
     maybeCrefType:
-      "{{#avoidCopy}}const {{/avoidCopy}}{{>maybeOmittableType}}{{>ref}}"
-    qualifiedMaybeCrefType:
-      "{{#avoidCopy}}const {{/avoidCopy}}{{>qualifiedMaybeOmittableType}}{{>ref}}"
+      "{{#avoidCopy}}const {{/avoidCopy}}{{>maybeOmittableType}}{{#avoidCopy}}&{{/avoidCopy}}"
 
     maybeCrefJsonObject:
       "{{^propertyMap}}const QJsonObject&{{/propertyMap}}\
diff --git a/gtad/operation.cpp.mustache b/gtad/operation.cpp.mustache
index 3d26ec73..4b75434c 100644
--- a/gtad/operation.cpp.mustache
+++ b/gtad/operation.cpp.mustache
@@ -34,20 +34,20 @@ QUrl {{camelCaseOperationId}}Job::makeRequestUrl(QUrl baseUrl{{#allParams?}},
 {   {{#headerParams}}
     setRequestHeader("{{baseName}}", {{paramName}}.toLatin1());
     {{/headerParams}}{{#inlineBody}}{{^propertyMap}}{{^bodyParams?}}
-    setRequestData(RequestData({{#consumesNonJson?}}{{nameCamelCase}}{{/consumesNonJson?
-    }}{{^consumesNonJson?}}toJson({{nameCamelCase}}){{/consumesNonJson?}}));
+    setRequestData({ {{#consumesNonJson?}}{{nameCamelCase}}{{/consumesNonJson?
+    }}{{^consumesNonJson?}}toJson({{nameCamelCase}}){{/consumesNonJson?}} });
     {{/bodyParams?}}{{/propertyMap}}{{/inlineBody
     }}{{^consumesNonJson?}}{{#bodyParams?}}
-    QJsonObject _data;
+    QJsonObject _dataJson;
         {{#propertyMap}}
-    fillJson(_data, {{nameCamelCase}});
+    fillJson(_dataJson, {{nameCamelCase}});
         {{/propertyMap}}{{#inlineBody}}
-    fillJson<{{>maybeOmittableType}}>(_data, {{paramName}});
+    fillJson<{{>maybeOmittableType}}>(_dataJson, {{paramName}});
         {{/inlineBody}}{{#bodyParams}}
-    addParam<{{^required?}}IfNotEmpty{{/required?}}>(_data,
+    addParam<{{^required?}}IfNotEmpty{{/required?}}>(_dataJson,
                     QStringLiteral("{{baseName}}"), {{paramName}});
         {{/bodyParams}}
-    setRequestData(std::move(_data));
+    setRequestData({ _dataJson });
     {{/bodyParams?}}{{/consumesNonJson?}}{{#producesNonJson?}}
     setExpectedContentTypes({ {{#produces}}"{{_}}"{{>cjoin}}{{/produces}} });
     {{/producesNonJson?}}{{^producesNonJson?
diff --git a/lib/accountregistry.cpp b/lib/accountregistry.cpp
index 616b54b4..ad7c5f99 100644
--- a/lib/accountregistry.cpp
+++ b/lib/accountregistry.cpp
@@ -5,6 +5,7 @@
 #include "accountregistry.h"
 
 #include "connection.h"
+#include <QtCore/QCoreApplication>
 
 using namespace Quotient;
 
@@ -15,14 +16,16 @@ void AccountRegistry::add(Connection* a)
     beginInsertRows(QModelIndex(), size(), size());
     push_back(a);
     endInsertRows();
+    emit accountCountChanged();
 }
 
 void AccountRegistry::drop(Connection* a)
 {
-    const auto idx = indexOf(a);
-    beginRemoveRows(QModelIndex(), idx, idx);
-    remove(idx);
-    endRemoveRows();
+    if (const auto idx = indexOf(a); idx != -1) {
+        beginRemoveRows(QModelIndex(), idx, idx);
+        remove(idx);
+        endRemoveRows();
+    }
     Q_ASSERT(!contains(a));
 }
 
@@ -54,8 +57,6 @@ QHash<int, QByteArray> AccountRegistry::roleNames() const
     return { { AccountRole, "connection" } };
 }
 
-
-
 Connection* AccountRegistry::get(const QString& userId)
 {
     for (const auto &connection : *this) {
@@ -64,3 +65,73 @@ Connection* AccountRegistry::get(const QString& userId)
     }
     return nullptr;
 }
+
+QKeychain::ReadPasswordJob* AccountRegistry::loadAccessTokenFromKeychain(const QString& userId)
+{
+    qCDebug(MAIN) << "Reading access token from keychain for" << userId;
+    auto job = new QKeychain::ReadPasswordJob(qAppName(), this);
+    job->setKey(userId);
+    job->start();
+
+    return job;
+}
+
+void AccountRegistry::invokeLogin()
+{
+    const auto accounts = SettingsGroup("Accounts").childGroups();
+    for (const auto& accountId : accounts) {
+        AccountSettings account { accountId };
+        m_accountsLoading += accountId;
+        emit accountsLoadingChanged();
+
+        if (account.homeserver().isEmpty())
+            continue;
+
+        auto accessTokenLoadingJob =
+            loadAccessTokenFromKeychain(account.userId());
+        connect(accessTokenLoadingJob, &QKeychain::Job::finished, this,
+                [accountId, this, accessTokenLoadingJob]() {
+                    if (accessTokenLoadingJob->error()
+                        != QKeychain::Error::NoError) {
+                        emit keychainError(accessTokenLoadingJob->error());
+                        return;
+                    }
+
+                    AccountSettings account { accountId };
+                    auto connection = new Connection(account.homeserver());
+                    connect(connection, &Connection::connected, this,
+                            [connection, this, accountId] {
+                                connection->loadState();
+                                connection->setLazyLoading(true);
+
+                                connection->syncLoop();
+
+                                m_accountsLoading.removeAll(accountId);
+                                emit accountsLoadingChanged();
+                            });
+                    connect(connection, &Connection::loginError, this,
+                            [this, connection, accountId](const QString& error,
+                                               const QString& details) {
+                                emit loginError(connection, error, details);
+
+                                m_accountsLoading.removeAll(accountId);
+                                emit accountsLoadingChanged();
+                            });
+                    connect(connection, &Connection::resolveError, this,
+                            [this, connection, accountId](const QString& error) {
+                                emit resolveError(connection, error);
+
+                                m_accountsLoading.removeAll(accountId);
+                                emit accountsLoadingChanged();
+                            });
+                    connection->assumeIdentity(
+                        account.userId(), accessTokenLoadingJob->binaryData(),
+                        account.deviceId());
+                });
+    }
+}
+
+QStringList AccountRegistry::accountsLoading() const
+{
+    return m_accountsLoading;
+}
diff --git a/lib/accountregistry.h b/lib/accountregistry.h
index 2f6dffdf..9560688e 100644
--- a/lib/accountregistry.h
+++ b/lib/accountregistry.h
@@ -5,18 +5,35 @@
 #pragma once
 
 #include "quotient_export.h"
+#include "settings.h"
 
 #include <QtCore/QAbstractListModel>
 
+#if QT_VERSION_MAJOR >= 6
+#    include <qt6keychain/keychain.h>
+#else
+#    include <qt5keychain/keychain.h>
+#endif
+
+namespace QKeychain {
+class ReadPasswordJob;
+}
+
 namespace Quotient {
 class Connection;
 
 class QUOTIENT_API AccountRegistry : public QAbstractListModel,
                                      private QVector<Connection*> {
     Q_OBJECT
+    /// Number of accounts that are currently fully loaded
+    Q_PROPERTY(int accountCount READ rowCount NOTIFY accountCountChanged)
+    /// List of accounts that are currently in some stage of being loaded (Reading token from keychain, trying to contact server, etc).
+    /// Can be used to inform the user or to show a login screen if size() == 0 and no accounts are loaded
+    Q_PROPERTY(QStringList accountsLoading READ accountsLoading NOTIFY accountsLoadingChanged)
 public:
-    using const_iterator = QVector::const_iterator;
-    using const_reference = QVector::const_reference;
+    using vector_t = QVector<Connection*>;
+    using const_iterator = vector_t::const_iterator;
+    using const_reference = vector_t::const_reference;
 
     enum EventRoles {
         AccountRole = Qt::UserRole + 1,
@@ -26,24 +43,24 @@ public:
     [[deprecated("Use Accounts variable instead")]] //
     static AccountRegistry& instance();
 
-    // Expose most of QVector's const-API but only provide add() and drop()
+    // Expose most of vector_t's const-API but only provide add() and drop()
     // for changing it. In theory other changing operations could be supported
     // too; but then boilerplate begin/end*() calls has to be tucked into each
     // and this class gives no guarantees on the order of entries, so why care.
 
-    const QVector<Connection*>& accounts() const { return *this; }
+    const vector_t& accounts() const { return *this; }
     void add(Connection* a);
     void drop(Connection* a);
-    const_iterator begin() const { return QVector::begin(); }
-    const_iterator end() const { return QVector::end(); }
-    const_reference front() const { return QVector::front(); }
-    const_reference back() const { return QVector::back(); }
+    const_iterator begin() const { return vector_t::begin(); }
+    const_iterator end() const { return vector_t::end(); }
+    const_reference front() const { return vector_t::front(); }
+    const_reference back() const { return vector_t::back(); }
     bool isLoggedIn(const QString& userId) const;
     Connection* get(const QString& userId);
 
-    using QVector::isEmpty, QVector::empty;
-    using QVector::size, QVector::count, QVector::capacity;
-    using QVector::cbegin, QVector::cend, QVector::contains;
+    using vector_t::isEmpty, vector_t::empty;
+    using vector_t::size, vector_t::count, vector_t::capacity;
+    using vector_t::cbegin, vector_t::cend, vector_t::contains;
 
     // QAbstractItemModel interface implementation
 
@@ -52,9 +69,24 @@ public:
     [[nodiscard]] int rowCount(
         const QModelIndex& parent = QModelIndex()) const override;
     [[nodiscard]] QHash<int, QByteArray> roleNames() const override;
+
+    QStringList accountsLoading() const;
+
+    void invokeLogin();
+Q_SIGNALS:
+    void accountCountChanged();
+    void accountsLoadingChanged();
+
+    void keychainError(QKeychain::Error error);
+    void loginError(Connection* connection, QString message, QString details);
+    void resolveError(Connection* connection, QString error);
+
+private:
+    QKeychain::ReadPasswordJob* loadAccessTokenFromKeychain(const QString &userId);
+    QStringList m_accountsLoading;
 };
 
 inline QUOTIENT_API AccountRegistry Accounts {};
 
 inline AccountRegistry& AccountRegistry::instance() { return Accounts; }
-}
+} // namespace Quotient
diff --git a/lib/avatar.cpp b/lib/avatar.cpp
index 9304a3de..13de99bf 100644
--- a/lib/avatar.cpp
+++ b/lib/avatar.cpp
@@ -39,7 +39,7 @@ public:
 
     // The below are related to image caching, hence mutable
     mutable QImage _originalImage;
-    mutable std::vector<QPair<QSize, QImage>> _scaledImages;
+    mutable std::vector<std::pair<QSize, QImage>> _scaledImages;
     mutable QSize _requestedSize;
     mutable enum { Unknown, Cache, Network, Banned } _imageSource = Unknown;
     mutable QPointer<MediaThumbnailJob> _thumbnailRequest = nullptr;
@@ -124,9 +124,9 @@ QImage Avatar::Private::get(Connection* connection, QSize size,
                          });
     }
 
-    for (const auto& p : _scaledImages)
-        if (p.first == size)
-            return p.second;
+    for (const auto& [scaledSize, scaledImage] : _scaledImages)
+        if (scaledSize == size)
+            return scaledImage;
     auto result = _originalImage.isNull()
                       ? QImage()
                       : _originalImage.scaled(size, Qt::KeepAspectRatio,
diff --git a/lib/connection.cpp b/lib/connection.cpp
index 68aed4e4..3e1e556f 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -36,23 +36,21 @@
 #include <variant>
 
 #ifdef Quotient_E2EE_ENABLED
-#    include "e2ee/qolmaccount.h"
-#    include "e2ee/qolmutils.h"
 #    include "database.h"
+#    include "e2ee/qolmaccount.h"
 #    include "e2ee/qolminboundsession.h"
+#    include "e2ee/qolmsession.h"
+#    include "e2ee/qolmutility.h"
+#    include "e2ee/qolmutils.h"
 #    include "events/keyverificationevent.h"
 #    include "keyverificationsession.h"
 
+#endif // Quotient_E2EE_ENABLED
 #if QT_VERSION_MAJOR >= 6
 #    include <qt6keychain/keychain.h>
 #else
 #    include <qt5keychain/keychain.h>
 #endif
-#endif // Quotient_E2EE_ENABLED
-
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
-#    include <QtCore/QCborValue>
-#endif
 
 #include <QtCore/QCoreApplication>
 #include <QtCore/QDir>
@@ -64,7 +62,6 @@
 #include <QtCore/QStringBuilder>
 #include <QtNetwork/QDnsLookup>
 
-
 using namespace Quotient;
 
 // This is very much Qt-specific; STL iterators don't have key() and value()
@@ -94,12 +91,11 @@ public:
     // state is Invited. The spec mandates to keep Invited room state
     // separately; specifically, we should keep objects for Invite and
     // Leave state of the same room if the two happen to co-exist.
-    QHash<QPair<QString, bool>, Room*> roomMap;
+    QHash<std::pair<QString, bool>, Room*> roomMap;
     /// Mapping from serverparts to alias/room id mappings,
     /// as of the last sync
     QHash<QString, QString> roomAliasMap;
     QVector<QString> roomIdsToForget;
-    QVector<Room*> firstTimeRooms;
     QVector<QString> pendingStateRoomIds;
     QMap<QString, User*> userMap;
     DirectChatsMap directChats;
@@ -182,15 +178,6 @@ public:
     void consumeToDeviceEvents(Events&& toDeviceEvents);
     void consumeDevicesList(DevicesList&& devicesList);
 
-    template <typename EventT>
-    EventT* unpackAccountData() const
-    {
-        const auto& eventIt = accountData.find(EventT::matrixTypeId());
-        return eventIt == accountData.end()
-                   ? nullptr
-                   : weakPtrCast<EventT>(eventIt->second);
-    }
-
     void packAndSendAccountData(EventPtr&& event)
     {
         const auto eventType = event->matrixType();
@@ -213,108 +200,85 @@ public:
 
 #ifdef Quotient_E2EE_ENABLED
     void loadSessions() {
-        olmSessions = q->database()->loadOlmSessions(q->picklingMode());
-    }
-    void saveSession(QOlmSessionPtr& session, const QString &senderKey) {
-        auto pickleResult = session->pickle(q->picklingMode());
-        if (std::holds_alternative<QOlmError>(pickleResult)) {
-            qCWarning(E2EE) << "Failed to pickle olm session. Error" << std::get<QOlmError>(pickleResult);
-            return;
-        }
-        q->database()->saveOlmSession(senderKey, session->sessionId(), std::get<QByteArray>(pickleResult), QDateTime::currentDateTime());
+        olmSessions = q->database()->loadOlmSessions(picklingMode);
     }
-    std::pair<QString, QString> sessionDecryptPrekey(const QOlmMessage& message, const QString &senderKey, std::unique_ptr<QOlmAccount>& olmAccount)
+    void saveSession(const QOlmSession& session, const QString& senderKey) const
     {
-        Q_ASSERT(message.type() == QOlmMessage::PreKey);
-        for (size_t i = 0; i < olmSessions[senderKey].size(); i++) {
-            auto& session = olmSessions[senderKey][i];
-            const auto matches = session->matchesInboundSessionFrom(senderKey, message);
-            if(std::holds_alternative<bool>(matches) && std::get<bool>(matches)) {
-                qCDebug(E2EE) << "Found inbound session";
-                const auto result = session->decrypt(message);
-                if(std::holds_alternative<QString>(result)) {
-                    q->database()->setOlmSessionLastReceived(QString(session->sessionId()), QDateTime::currentDateTime());
-                    auto pickle = session->pickle(q->picklingMode());
-                    if (std::holds_alternative<QByteArray>(pickle)) {
-                        q->database()->updateOlmSession(senderKey, session->sessionId(), std::get<QByteArray>(pickle));
-                    } else {
-                        qCWarning(E2EE) << "Failed to pickle olm session.";
-                    }
-                    auto s = std::move(session);
-                    olmSessions[senderKey].erase(olmSessions[senderKey].begin() + i);
-                    olmSessions[senderKey].insert(olmSessions[senderKey].begin(), std::move(s));
-                    return { std::get<QString>(result), olmSessions[senderKey][0]->sessionId() };
-                } else {
-                    qCDebug(E2EE) << "Failed to decrypt prekey message";
-                    return {};
-                }
-            }
-        }
-        qCDebug(E2EE) << "Creating new inbound session";
-        auto newSessionResult = olmAccount->createInboundSessionFrom(senderKey.toUtf8(), message);
-        if(std::holds_alternative<QOlmError>(newSessionResult)) {
-            qCWarning(E2EE) << "Failed to create inbound session for" << senderKey << std::get<QOlmError>(newSessionResult);
-            return {};
-        }
-        auto newSession = std::move(std::get<QOlmSessionPtr>(newSessionResult));
-        auto error = olmAccount->removeOneTimeKeys(newSession);
-        if (error) {
-            qWarning(E2EE) << "Failed to remove one time key for session" << newSession->sessionId();
-        }
-        const auto result = newSession->decrypt(message);
-        QString sessionId = newSession->sessionId();
-        saveSession(newSession, senderKey);
-        olmSessions[senderKey].insert(olmSessions[senderKey].begin(), std::move(newSession));
-        if(std::holds_alternative<QString>(result)) {
-            return { std::get<QString>(result), sessionId };
-        } else {
-            qCDebug(E2EE) << "Failed to decrypt prekey message with new session";
-            return {};
-        }
+        if (auto pickleResult = session.pickle(picklingMode))
+            q->database()->saveOlmSession(senderKey, session.sessionId(),
+                                          *pickleResult,
+                                          QDateTime::currentDateTime());
+        else
+            qCWarning(E2EE) << "Failed to pickle olm session. Error"
+                            << pickleResult.error();
     }
-    std::pair<QString, QString> sessionDecryptGeneral(const QOlmMessage& message, const QString &senderKey)
+
+    template <typename FnT>
+    std::pair<QString, QString> doDecryptMessage(const QOlmSession& session,
+                                                 const QOlmMessage& message,
+                                                 FnT&& andThen) const
     {
-        Q_ASSERT(message.type() == QOlmMessage::General);
-        for (size_t i = 0; i < olmSessions[senderKey].size(); i++) {
-            auto& session = olmSessions[senderKey][i];
-            const auto result = session->decrypt(message);
-            if(std::holds_alternative<QString>(result)) {
-                q->database()->setOlmSessionLastReceived(QString(session->sessionId()), QDateTime::currentDateTime());
-                auto pickle = session->pickle(q->picklingMode());
-                if (std::holds_alternative<QByteArray>(pickle)) {
-                    q->database()->updateOlmSession(senderKey, session->sessionId(), std::get<QByteArray>(pickle));
-                } else {
-                    qCWarning(E2EE) << "Failed to pickle olm session.";
-                }
-                auto s = std::move(session);
-                olmSessions[senderKey].erase(olmSessions[senderKey].begin() + i);
-                olmSessions[senderKey].insert(olmSessions[senderKey].begin(), std::move(s));
-                return { std::get<QString>(result), olmSessions[senderKey][0]->sessionId() };
-            }
+        const auto expectedMessage = session.decrypt(message);
+        if (expectedMessage) {
+            const auto result =
+                std::make_pair(*expectedMessage, session.sessionId());
+            andThen();
+            return result;
         }
-        qCWarning(E2EE) << "Failed to decrypt message";
+        const auto errorLine = message.type() == QOlmMessage::PreKey
+                                   ? "Failed to decrypt prekey message:"
+                                   : "Failed to decrypt message:";
+        qCDebug(E2EE) << errorLine << expectedMessage.error();
         return {};
     }
 
     std::pair<QString, QString> sessionDecryptMessage(
-        const QJsonObject& personalCipherObject, const QByteArray& senderKey, std::unique_ptr<QOlmAccount>& account)
+        const QJsonObject& personalCipherObject, const QByteArray& senderKey)
     {
-        QString decrypted;
-        QString olmSessionId;
-        int type = personalCipherObject.value(TypeKeyL).toInt(-1);
-        QByteArray body = personalCipherObject.value(BodyKeyL).toString().toLatin1();
-        if (type == QOlmMessage::PreKey) {
-            QOlmMessage preKeyMessage(body, QOlmMessage::PreKey);
-            auto result = sessionDecryptPrekey(preKeyMessage, senderKey, account);
-            decrypted = result.first;
-            olmSessionId = result.second;
-        } else if (type == QOlmMessage::General) {
-            QOlmMessage message(body, QOlmMessage::General);
-            auto result = sessionDecryptGeneral(message, senderKey);
-            decrypted = result.first;
-            olmSessionId = result.second;
+        const auto msgType = static_cast<QOlmMessage::Type>(
+            personalCipherObject.value(TypeKeyL).toInt(-1));
+        if (msgType != QOlmMessage::General && msgType != QOlmMessage::PreKey) {
+            qCWarning(E2EE) << "Olm message has incorrect type" << msgType;
+            return {};
         }
-        return { decrypted, olmSessionId };
+        QOlmMessage message {
+            personalCipherObject.value(BodyKeyL).toString().toLatin1(), msgType
+        };
+        for (const auto& session : olmSessions[senderKey])
+            if (msgType == QOlmMessage::General
+                || session->matchesInboundSessionFrom(senderKey, message)) {
+                return doDecryptMessage(*session, message, [this, &session] {
+                    q->database()->setOlmSessionLastReceived(
+                        session->sessionId(), QDateTime::currentDateTime());
+                });
+            }
+
+        if (msgType == QOlmMessage::General) {
+            qCWarning(E2EE) << "Failed to decrypt message";
+            return {};
+        }
+
+        qCDebug(E2EE) << "Creating new inbound session"; // Pre-key messages only
+        auto newSessionResult =
+            olmAccount->createInboundSessionFrom(senderKey, message);
+        if (!newSessionResult) {
+            qCWarning(E2EE)
+                << "Failed to create inbound session for" << senderKey
+                << "with error" << newSessionResult.error();
+            return {};
+        }
+        auto newSession = std::move(*newSessionResult);
+        auto error = olmAccount->removeOneTimeKeys(*newSession);
+        if (error) {
+            qWarning(E2EE) << "Failed to remove one time key for session"
+                           << newSession->sessionId();
+            // Keep going though
+        }
+        return doDecryptMessage(
+            *newSession, message, [this, &senderKey, &newSession] {
+                saveSession(*newSession, senderKey);
+                olmSessions[senderKey].push_back(std::move(newSession));
+            });
     }
 #endif
 
@@ -334,8 +298,9 @@ public:
             qCDebug(E2EE) << "Encrypted event is not for the current device";
             return {};
         }
-        const auto [decrypted, olmSessionId] = sessionDecryptMessage(
-            personalCipherObject, encryptedEvent.senderKey().toLatin1(), olmAccount);
+        const auto [decrypted, olmSessionId] =
+            sessionDecryptMessage(personalCipherObject,
+                                  encryptedEvent.senderKey().toLatin1());
         if (decrypted.isEmpty()) {
             qCDebug(E2EE) << "Problem with new session from senderKey:"
                           << encryptedEvent.senderKey()
@@ -389,10 +354,53 @@ public:
 #endif // Quotient_E2EE_ENABLED
     }
 #ifdef Quotient_E2EE_ENABLED
+    bool isKnownCurveKey(const QString& userId, const QString& curveKey) const;
+
     void loadOutdatedUserDevices();
     void saveDevicesList();
     void loadDevicesList();
+
+    // This function assumes that an olm session with (user, device) exists
+    std::pair<QOlmMessage::Type, QByteArray> olmEncryptMessage(
+        const QString& userId, const QString& device,
+        const QByteArray& message) const;
+    bool createOlmSession(const QString& targetUserId,
+                          const QString& targetDeviceId,
+                          const OneTimeKeys &oneTimeKeyObject);
+    QString curveKeyForUserDevice(const QString& userId,
+                                  const QString& device) const;
+    QJsonObject encryptSessionKeyEvent(QJsonObject payloadJson,
+                                       const QString& targetUserId,
+                                       const QString& targetDeviceId) const;
 #endif
+
+    void saveAccessTokenToKeychain() const
+    {
+        qCDebug(MAIN) << "Saving access token to keychain for" << q->userId();
+        auto job = new QKeychain::WritePasswordJob(qAppName());
+        job->setAutoDelete(false);
+        job->setKey(q->userId());
+        job->setBinaryData(data->accessToken());
+        job->start();
+        //TODO error handling
+    }
+
+    void dropAccessToken()
+    {
+        qCDebug(MAIN) << "Removing access token from keychain for" << q->userId();
+        auto job = new QKeychain::DeletePasswordJob(qAppName());
+        job->setAutoDelete(true);
+        job->setKey(q->userId());
+        job->start();
+
+        auto pickleJob = new QKeychain::DeletePasswordJob(qAppName());
+        pickleJob->setAutoDelete(true);
+        pickleJob->setKey(q->userId() + "-Pickle"_ls);
+        pickleJob->start();
+        //TODO error handling
+
+        data->setToken({});
+    }
 };
 
 Connection::Connection(const QUrl& server, QObject* parent)
@@ -571,11 +579,10 @@ void Connection::Private::loginToServer(LoginArgTs&&... loginArgs)
         data->setToken(loginJob->accessToken().toLatin1());
         data->setDeviceId(loginJob->deviceId());
         completeSetup(loginJob->userId());
-#ifndef Quotient_E2EE_ENABLED
-        qCWarning(E2EE) << "End-to-end encryption (E2EE) support is turned off.";
-#else // Quotient_E2EE_ENABLED
+        saveAccessTokenToKeychain();
+#ifdef Quotient_E2EE_ENABLED
         database->clear();
-#endif // Quotient_E2EE_ENABLED
+#endif
     });
     connect(loginJob, &BaseJob::failure, q, [this, loginJob] {
         emit q->loginError(loginJob->errorString(), loginJob->rawDataSample());
@@ -591,6 +598,7 @@ void Connection::Private::completeSetup(const QString& mxId)
                   << "by user" << data->userId()
                   << "from device" << data->deviceId();
     Accounts.add(q);
+    connect(qApp, &QCoreApplication::aboutToQuit, q, &Connection::saveState);
 #ifndef Quotient_E2EE_ENABLED
     qCWarning(E2EE) << "End-to-end encryption (E2EE) support is turned off.";
 #else // Quotient_E2EE_ENABLED
@@ -632,9 +640,7 @@ void Connection::Private::completeSetup(const QString& mxId)
     olmAccount = std::make_unique<QOlmAccount>(data->userId(), data->deviceId(), q);
     connect(olmAccount.get(), &QOlmAccount::needsSave, q, &Connection::saveOlmAccount);
 
-#ifdef Quotient_E2EE_ENABLED
     loadSessions();
-#endif
 
     if (database->accountPickle().isEmpty()) {
         // create new account and save unpickle data
@@ -707,7 +713,8 @@ void Connection::logout()
             || d->logoutJob->error() == BaseJob::ContentAccessError) {
             if (d->syncLoopConnection)
                 disconnect(d->syncLoopConnection);
-            d->data->setToken({});
+            SettingsGroup("Accounts").remove(userId());
+            d->dropAccessToken();
             emit loggedOut();
             deleteLater();
         } else { // logout() somehow didn't proceed - restore the session state
@@ -856,16 +863,14 @@ void Connection::Private::consumeRoomData(SyncDataList&& roomDataList,
         }
         if (auto* r = q->provideRoom(roomData.roomId, roomData.joinState)) {
             pendingStateRoomIds.removeOne(roomData.roomId);
-            r->updateData(std::move(roomData), fromCache);
-            if (firstTimeRooms.removeOne(r)) {
-                emit q->loadedRoomState(r);
-                if (capabilities.roomVersions)
-                    r->checkVersion();
-                // Otherwise, the version will be checked in reloadCapabilities()
-            }
+            // Update rooms one by one, giving time to update the UI.
+            QMetaObject::invokeMethod(
+                r,
+                [r, rd = std::move(roomData), fromCache] () mutable {
+                    r->updateData(std::move(rd), fromCache);
+                },
+                Qt::QueuedConnection);
         }
-        // Let UI update itself after updating each room
-        QCoreApplication::processEvents();
     }
 }
 
@@ -962,38 +967,45 @@ void Connection::Private::consumeToDeviceEvents(Events&& toDeviceEvents)
 {
 #ifdef Quotient_E2EE_ENABLED
     if (!toDeviceEvents.empty()) {
-        qCDebug(E2EE) << "Consuming" << toDeviceEvents.size() << "to-device events";
-        visitEach(toDeviceEvents, [this](const EncryptedEvent& event) {
-            if (event.algorithm() != OlmV1Curve25519AesSha2AlgoKey) {
-                qCDebug(E2EE) << "Unsupported algorithm" << event.id() << "for event" << event.algorithm();
-                return;
-            }
-            if (q->isKnownCurveKey(event.senderId(), event.senderKey())) {
-                handleEncryptedToDeviceEvent(event);
-                return;
+        qCDebug(E2EE) << "Consuming" << toDeviceEvents.size()
+                      << "to-device events";
+        for (auto&& tdEvt : toDeviceEvents) {
+            if (auto&& event = eventCast<EncryptedEvent>(std::move(tdEvt))) {
+                if (event->algorithm() != OlmV1Curve25519AesSha2AlgoKey) {
+                    qCDebug(E2EE) << "Unsupported algorithm" << event->id()
+                                  << "for event" << event->algorithm();
+                    return;
+                }
+                if (isKnownCurveKey(event->senderId(), event->senderKey())) {
+                    handleEncryptedToDeviceEvent(*event);
+                    return;
+                }
+                trackedUsers += event->senderId();
+                outdatedUsers += event->senderId();
+                encryptionUpdateRequired = true;
+                pendingEncryptedEvents.push_back(std::move(event));
+                continue;
             }
-            trackedUsers += event.senderId();
-            outdatedUsers += event.senderId();
-            encryptionUpdateRequired = true;
-            pendingEncryptedEvents.push_back(std::make_unique<EncryptedEvent>(event.fullJson()));
-        }, [this](const KeyVerificationRequestEvent& event) {
-            auto session = new KeyVerificationSession(q->userId(), event, q, false, q);
-            emit q->newKeyVerificationSession(session);
-        }, [this](const KeyVerificationReadyEvent& event) {
-            emit q->incomingKeyVerificationReady(event);
-        }, [this](const KeyVerificationStartEvent& event) {
-            emit q->incomingKeyVerificationStart(event);
-        }, [this](const KeyVerificationAcceptEvent& event) {
-            emit q->incomingKeyVerificationAccept(event);
-        }, [this](const KeyVerificationKeyEvent& event) {
-            emit q->incomingKeyVerificationKey(event);
-        }, [this](const KeyVerificationMacEvent& event) {
-            emit q->incomingKeyVerificationMac(event);
-        }, [this](const KeyVerificationDoneEvent& event) {
-            emit q->incomingKeyVerificationDone(event);
-        }, [this](const KeyVerificationCancelEvent& event) {
-            emit q->incomingKeyVerificationCancel(event);
-        });
+            switchOnType(*tdEvt,
+                [this](const KeyVerificationRequestEvent& event) {
+                    auto session = new KeyVerificationSession(q->userId(), event, q, false, q);
+                    emit q->newKeyVerificationSession(session);
+                }, [this](const KeyVerificationReadyEvent& event) {
+                    emit q->incomingKeyVerificationReady(event);
+                }, [this](const KeyVerificationStartEvent& event) {
+                    emit q->incomingKeyVerificationStart(event);
+                }, [this](const KeyVerificationAcceptEvent& event) {
+                    emit q->incomingKeyVerificationAccept(event);
+                }, [this](const KeyVerificationKeyEvent& event) {
+                    emit q->incomingKeyVerificationKey(event);
+                }, [this](const KeyVerificationMacEvent& event) {
+                    emit q->incomingKeyVerificationMac(event);
+                }, [this](const KeyVerificationDoneEvent& event) {
+                    emit q->incomingKeyVerificationDone(event);
+                }, [this](const KeyVerificationCancelEvent& event) {
+                    emit q->incomingKeyVerificationCancel(event);
+                });
+        }
     }
 #endif
 }
@@ -1008,7 +1020,7 @@ void Connection::Private::handleEncryptedToDeviceEvent(const EncryptedEvent& eve
     }
 
     switchOnType(*decryptedEvent,
-        [this, senderKey = event.senderKey(), &event, olmSessionId = olmSessionId](const RoomKeyEvent& roomKeyEvent) {
+        [this, &event, olmSessionId = olmSessionId](const RoomKeyEvent& roomKeyEvent) {
             if (auto* detectedRoom = q->room(roomKeyEvent.roomId())) {
                 detectedRoom->handleRoomKeyEvent(roomKeyEvent, event.senderId(), olmSessionId);
             } else {
@@ -1197,15 +1209,14 @@ DownloadFileJob* Connection::downloadFile(const QUrl& url,
 }
 
 #ifdef Quotient_E2EE_ENABLED
-DownloadFileJob* Connection::downloadFile(const QUrl& url,
-                                          const EncryptedFile& file,
-                                          const QString& localFilename)
+DownloadFileJob* Connection::downloadFile(
+    const QUrl& url, const EncryptedFileMetadata& fileMetadata,
+    const QString& localFilename)
 {
     auto mediaId = url.authority() + url.path();
     auto idParts = splitMediaId(mediaId);
-    auto* job =
-        callApi<DownloadFileJob>(idParts.front(), idParts.back(), file, localFilename);
-    return job;
+    return callApi<DownloadFileJob>(idParts.front(), idParts.back(),
+                                    fileMetadata, localFilename);
 }
 #endif
 
@@ -1377,26 +1388,11 @@ ForgetRoomJob* Connection::forgetRoom(const QString& id)
     return forgetJob;
 }
 
-SendToDeviceJob*
-Connection::sendToDevices(const QString& eventType,
-                          const UsersToDevicesToEvents& eventsMap)
-{
-    QHash<QString, QHash<QString, QJsonObject>> json;
-    json.reserve(int(eventsMap.size()));
-    std::for_each(eventsMap.begin(), eventsMap.end(),
-                  [&json](const auto& userTodevicesToEvents) {
-                      auto& jsonUser = json[userTodevicesToEvents.first];
-                      const auto& devicesToEvents = userTodevicesToEvents.second;
-                      std::for_each(devicesToEvents.begin(),
-                                    devicesToEvents.end(),
-                                    [&jsonUser](const auto& deviceToEvents) {
-                                        jsonUser.insert(
-                                            deviceToEvents.first,
-                                            deviceToEvents.second->contentJson());
-                                    });
-                  });
+SendToDeviceJob* Connection::sendToDevices(
+    const QString& eventType, const UsersToDevicesToContent& contents)
+{
     return callApi<SendToDeviceJob>(BackgroundRequest, eventType,
-                                    generateTxnId(), json);
+                                    generateTxnId(), contents);
 }
 
 SendMessageJob* Connection::sendMessage(const QString& roomId,
@@ -1489,12 +1485,14 @@ User* Connection::user(const QString& uId)
 {
     if (uId.isEmpty())
         return nullptr;
+    if (const auto v = d->userMap.value(uId, nullptr))
+        return v;
+    // Before creating a user object, check that the user id is well-formed
+    // (it's faster to just do a lookup above before validation)
     if (!uId.startsWith('@') || serverPart(uId).isEmpty()) {
         qCCritical(MAIN) << "Malformed userId:" << uId;
         return nullptr;
     }
-    if (d->userMap.contains(uId))
-        return d->userMap.value(uId);
     auto* user = userFactory()(this, uId);
     d->userMap.insert(uId, user);
     emit newUser(user);
@@ -1696,7 +1694,7 @@ bool Connection::isIgnored(const User* user) const
 
 IgnoredUsersList Connection::ignoredUsers() const
 {
-    const auto* event = d->unpackAccountData<IgnoredUsersEvent>();
+    const auto* event = accountData<IgnoredUsersEvent>();
     return event ? event->ignored_users() : IgnoredUsersList();
 }
 
@@ -1736,7 +1734,7 @@ Room* Connection::provideRoom(const QString& id, Omittable<JoinState> joinState)
     Q_ASSERT_X(!id.isEmpty(), __FUNCTION__, "Empty room id");
 
     // If joinState is empty, all joinState == comparisons below are false.
-    const auto roomKey = qMakePair(id, joinState == JoinState::Invite);
+    const std::pair roomKey { id, joinState == JoinState::Invite };
     auto* room = d->roomMap.value(roomKey, nullptr);
     if (room) {
         // Leave is a special case because in transition (5a) (see the .h file)
@@ -1761,9 +1759,14 @@ Room* Connection::provideRoom(const QString& id, Omittable<JoinState> joinState)
             return nullptr;
         }
         d->roomMap.insert(roomKey, room);
-        d->firstTimeRooms.push_back(room);
         connect(room, &Room::beforeDestruction, this,
                 &Connection::aboutToDeleteRoom);
+        connect(room, &Room::baseStateLoaded, this, [this, room] {
+            emit loadedRoomState(room);
+            if (d->capabilities.roomVersions)
+                room->checkVersion();
+            // Otherwise, the version will be checked in reloadCapabilities()
+        });
         emit newRoom(room);
     }
     if (!joinState)
@@ -1850,16 +1853,10 @@ void Connection::saveRoomState(Room* r) const
     QFile outRoomFile { stateCacheDir().filePath(
         SyncData::fileNameForRoom(r->id())) };
     if (outRoomFile.open(QFile::WriteOnly)) {
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
         const auto data =
             d->cacheToBinary
                 ? QCborValue::fromJsonValue(r->toJson()).toCbor()
                 : QJsonDocument(r->toJson()).toJson(QJsonDocument::Compact);
-#else
-        QJsonDocument json { r->toJson() };
-        const auto data = d->cacheToBinary ? json.toBinaryData()
-                                           : json.toJson(QJsonDocument::Compact);
-#endif
         outRoomFile.write(data.data(), data.size());
         qCDebug(MAIN) << "Room state cache saved to" << outRoomFile.fileName();
     } else {
@@ -1912,11 +1909,11 @@ void Connection::saveState() const
     }
     {
         QJsonArray accountDataEvents {
-            basicEventJson(QStringLiteral("m.direct"), toJson(d->directChats))
+            Event::basicJson(QStringLiteral("m.direct"), toJson(d->directChats))
         };
         for (const auto& e : d->accountData)
             accountDataEvents.append(
-                basicEventJson(e.first, e.second->contentJson()));
+                Event::basicJson(e.first, e.second->contentJson()));
 
         rootObj.insert(QStringLiteral("account_data"),
                        QJsonObject {
@@ -1929,15 +1926,9 @@ void Connection::saveState() const
     }
 #endif
 
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
     const auto data =
         d->cacheToBinary ? QCborValue::fromJsonValue(rootObj).toCbor()
                          : QJsonDocument(rootObj).toJson(QJsonDocument::Compact);
-#else
-    QJsonDocument json { rootObj };
-    const auto data = d->cacheToBinary ? json.toBinaryData()
-                                       : json.toJson(QJsonDocument::Compact);
-#endif
     qCDebug(PROFILER) << "Cache for" << userId() << "generated in" << et;
 
     outFile.write(data.data(), data.size());
@@ -2119,19 +2110,20 @@ void Connection::Private::loadOutdatedUserDevices()
                         continue;
                     }
                 }
-                deviceKeys[user][device.deviceId] = device;
+                deviceKeys[user][device.deviceId] = SLICE(device, DeviceKeys);
             }
             outdatedUsers -= user;
         }
         saveDevicesList();
 
         for(size_t i = 0; i < pendingEncryptedEvents.size();) {
-            if (q->isKnownCurveKey(pendingEncryptedEvents[i]->fullJson()[SenderKeyL].toString(), pendingEncryptedEvents[i]->contentJson()["sender_key"].toString())) {
-                handleEncryptedToDeviceEvent(*(pendingEncryptedEvents[i].get()));
+            if (isKnownCurveKey(
+                    pendingEncryptedEvents[i]->fullJson()[SenderKeyL].toString(),
+                    pendingEncryptedEvents[i]->contentPart<QString>("sender_key"_ls))) {
+                handleEncryptedToDeviceEvent(*pendingEncryptedEvents[i]);
                 pendingEncryptedEvents.erase(pendingEncryptedEvents.begin() + i);
-            } else {
-                i++;
-            }
+            } else
+                ++i;
         }
     });
 }
@@ -2234,101 +2226,236 @@ void Connection::saveOlmAccount()
 {
     qCDebug(E2EE) << "Saving olm account";
 #ifdef Quotient_E2EE_ENABLED
-    auto pickle = d->olmAccount->pickle(d->picklingMode);
-    d->database->setAccountPickle(std::get<QByteArray>(pickle));
+    if (const auto expectedPickle = d->olmAccount->pickle(d->picklingMode))
+        d->database->setAccountPickle(*expectedPickle);
+    else
+        qCWarning(E2EE) << "Couldn't save Olm account pickle:"
+                        << expectedPickle.error();
 #endif
 }
 
 #ifdef Quotient_E2EE_ENABLED
 QJsonObject Connection::decryptNotification(const QJsonObject &notification)
 {
-    auto room = this->room(notification["room_id"].toString());
+    auto r = room(notification["room_id"].toString());
     auto event = makeEvent<EncryptedEvent>(notification["event"].toObject());
-    auto decrypted = room->decryptMessage(*event);
-    if(!decrypted) {
-        return QJsonObject();
-    }
-    return decrypted->fullJson();
+    const auto decrypted = r->decryptMessage(*event);
+    return decrypted ? decrypted->fullJson() : QJsonObject();
 }
 
-Database* Connection::database()
+Database* Connection::database() const
 {
     return d->database;
 }
 
-UnorderedMap<QString, QOlmInboundGroupSessionPtr> Connection::loadRoomMegolmSessions(Room* room)
+UnorderedMap<QString, QOlmInboundGroupSessionPtr>
+Connection::loadRoomMegolmSessions(const Room* room) const
 {
     return database()->loadMegolmSessions(room->id(), picklingMode());
 }
 
-void Connection::saveMegolmSession(Room* room, QOlmInboundGroupSession* session)
+void Connection::saveMegolmSession(const Room* room,
+                                   const QOlmInboundGroupSession& session) const
 {
-    database()->saveMegolmSession(room->id(), session->sessionId(), session->pickle(picklingMode()), session->senderId(), session->olmSessionId());
+    database()->saveMegolmSession(room->id(), session.sessionId(),
+                                  session.pickle(picklingMode()),
+                                  session.senderId(), session.olmSessionId());
 }
 
-QStringList Connection::devicesForUser(User* user) const
+QStringList Connection::devicesForUser(const QString& userId) const
 {
-    return d->deviceKeys[user->id()].keys();
+    return d->deviceKeys[userId].keys();
 }
 
-QString Connection::curveKeyForUserDevice(const QString& user, const QString& device) const
+QString Connection::Private::curveKeyForUserDevice(const QString& userId,
+                                                   const QString& device) const
 {
-    return d->deviceKeys[user][device].keys["curve25519:" % device];
+    return deviceKeys[userId][device].keys["curve25519:" % device];
 }
 
-QString Connection::edKeyForUserDevice(const QString& user, const QString& device) const
+QString Connection::edKeyForUserDevice(const QString& userId,
+                                       const QString& device) const
 {
-    return d->deviceKeys[user][device].keys["ed25519:" % device];
+    return d->deviceKeys[userId][device].keys["ed25519:" % device];
 }
 
-bool Connection::hasOlmSession(User* user, const QString& deviceId) const
+bool Connection::Private::isKnownCurveKey(const QString& userId,
+                                          const QString& curveKey) const
 {
-    const auto& curveKey = curveKeyForUserDevice(user->id(), deviceId);
-    return d->olmSessions.contains(curveKey) && d->olmSessions[curveKey].size() > 0;
+    auto query = database->prepareQuery(
+        QStringLiteral("SELECT * FROM tracked_devices WHERE matrixId=:matrixId "
+                       "AND curveKey=:curveKey"));
+    query.bindValue(":matrixId", userId);
+    query.bindValue(":curveKey", curveKey);
+    database->execute(query);
+    return query.next();
 }
 
-QPair<QOlmMessage::Type, QByteArray> Connection::olmEncryptMessage(User* user, const QString& device, const QByteArray& message)
+bool Connection::hasOlmSession(const QString& user,
+                               const QString& deviceId) const
 {
-    const auto& curveKey = curveKeyForUserDevice(user->id(), device);
-    QOlmMessage::Type type = d->olmSessions[curveKey][0]->encryptMessageType();
-    auto result = d->olmSessions[curveKey][0]->encrypt(message);
-    auto pickle = d->olmSessions[curveKey][0]->pickle(picklingMode());
-    if (std::holds_alternative<QByteArray>(pickle)) {
-        database()->updateOlmSession(curveKey, d->olmSessions[curveKey][0]->sessionId(), std::get<QByteArray>(pickle));
+    const auto& curveKey = d->curveKeyForUserDevice(user, deviceId);
+    return d->olmSessions.contains(curveKey) && !d->olmSessions[curveKey].empty();
+}
+
+std::pair<QOlmMessage::Type, QByteArray> Connection::Private::olmEncryptMessage(
+    const QString& userId, const QString& device,
+    const QByteArray& message) const
+{
+    const auto& curveKey = curveKeyForUserDevice(userId, device);
+    const auto& olmSession = olmSessions.at(curveKey).front();
+    QOlmMessage::Type type = olmSession->encryptMessageType();
+    const auto result = olmSession->encrypt(message);
+    if (const auto pickle = olmSession->pickle(picklingMode)) {
+        database->updateOlmSession(curveKey, olmSession->sessionId(), *pickle);
     } else {
-        qCWarning(E2EE) << "Failed to pickle olm session.";
+        qWarning(E2EE) << "Failed to pickle olm session: " << pickle.error();
     }
-    return qMakePair(type, result.toCiphertext());
+    return { type, result.toCiphertext() };
 }
 
-void Connection::createOlmSession(const QString& theirIdentityKey, const QString& theirOneTimeKey)
+bool Connection::Private::createOlmSession(const QString& targetUserId,
+                                           const QString& targetDeviceId,
+                                           const OneTimeKeys& oneTimeKeyObject)
 {
-    auto session = QOlmSession::createOutboundSession(olmAccount(), theirIdentityKey, theirOneTimeKey);
-    if (std::holds_alternative<QOlmError>(session)) {
-        qCWarning(E2EE) << "Failed to create olm session for " << theirIdentityKey << std::get<QOlmError>(session);
-        return;
+    static QOlmUtility verifier;
+    qDebug(E2EE) << "Creating a new session for" << targetUserId
+                 << targetDeviceId;
+    if (oneTimeKeyObject.isEmpty()) {
+        qWarning(E2EE) << "No one time key for" << targetUserId
+                       << targetDeviceId;
+        return false;
     }
-    d->saveSession(std::get<std::unique_ptr<QOlmSession>>(session), theirIdentityKey);
-    d->olmSessions[theirIdentityKey].push_back(std::move(std::get<std::unique_ptr<QOlmSession>>(session)));
+    auto* signedOneTimeKey =
+        std::get_if<SignedOneTimeKey>(&*oneTimeKeyObject.begin());
+    if (!signedOneTimeKey) {
+        qWarning(E2EE) << "No signed one time key for" << targetUserId
+                       << targetDeviceId;
+        return false;
+    }
+    // Verify contents of signedOneTimeKey - for that, drop `signatures` and
+    // `unsigned` and then verify the object against the respective signature
+    const auto signature =
+        signedOneTimeKey->signature(targetUserId, targetDeviceId);
+    if (!verifier.ed25519Verify(
+            q->edKeyForUserDevice(targetUserId, targetDeviceId).toLatin1(),
+            signedOneTimeKey->toJsonForVerification(),
+            signature)) {
+        qWarning(E2EE) << "Failed to verify one-time-key signature for"
+                       << targetUserId << targetDeviceId
+                       << ". Skipping this device.";
+        return false;
+    }
+    const auto recipientCurveKey =
+        curveKeyForUserDevice(targetUserId, targetDeviceId);
+    auto session =
+        QOlmSession::createOutboundSession(olmAccount.get(), recipientCurveKey,
+                                           signedOneTimeKey->key());
+    if (!session) {
+        qCWarning(E2EE) << "Failed to create olm session for "
+                        << recipientCurveKey << session.error();
+        return false;
+    }
+    saveSession(**session, recipientCurveKey);
+    olmSessions[recipientCurveKey].push_back(std::move(*session));
+    return true;
+}
+
+QJsonObject Connection::Private::encryptSessionKeyEvent(
+    QJsonObject payloadJson, const QString& targetUserId,
+    const QString& targetDeviceId) const
+{
+    payloadJson.insert("recipient"_ls, targetUserId);
+    payloadJson.insert(
+        "recipient_keys"_ls,
+        QJsonObject{ { Ed25519Key,
+                       q->edKeyForUserDevice(targetUserId, targetDeviceId) } });
+    const auto [type, cipherText] = olmEncryptMessage(
+        targetUserId, targetDeviceId,
+        QJsonDocument(payloadJson).toJson(QJsonDocument::Compact));
+    QJsonObject encrypted {
+        { curveKeyForUserDevice(targetUserId, targetDeviceId),
+          QJsonObject { { "type"_ls, type },
+                        { "body"_ls, QString(cipherText) } } }
+    };
+
+    return EncryptedEvent(encrypted, olmAccount->identityKeys().curve25519)
+        .contentJson();
 }
 
-QOlmOutboundGroupSessionPtr Connection::loadCurrentOutboundMegolmSession(Room* room)
+void Connection::sendSessionKeyToDevices(
+    const QString& roomId, const QByteArray& sessionId,
+    const QByteArray& sessionKey, const QMultiHash<QString, QString>& devices,
+    int index)
 {
-    return d->database->loadCurrentOutboundMegolmSession(room->id(), d->picklingMode);
+    qDebug(E2EE) << "Sending room key to devices:" << sessionId
+                 << sessionKey.toHex();
+    QHash<QString, QHash<QString, QString>> hash;
+    for (const auto& [userId, deviceId] : asKeyValueRange(devices))
+        if (!hasOlmSession(userId, deviceId)) {
+            hash[userId].insert(deviceId, "signed_curve25519"_ls);
+            qDebug(E2EE) << "Adding" << userId << deviceId
+                         << "to keys to claim";
+        }
+
+    if (hash.isEmpty())
+        return;
+
+    auto keyEventJson = RoomKeyEvent(MegolmV1AesSha2AlgoKey, roomId, sessionId,
+                                     sessionKey, userId())
+                            .fullJson();
+    keyEventJson.insert(SenderKeyL, userId());
+    keyEventJson.insert("sender_device"_ls, deviceId());
+    keyEventJson.insert(
+        "keys"_ls,
+        QJsonObject {
+            { Ed25519Key, QString(olmAccount()->identityKeys().ed25519) } });
+
+    auto job = callApi<ClaimKeysJob>(hash);
+    connect(job, &BaseJob::success, this, [job, this, roomId, sessionId, keyEventJson, devices, index] {
+        QHash<QString, QHash<QString, QJsonObject>> usersToDevicesToContent;
+        for (const auto oneTimeKeys = job->oneTimeKeys();
+             const auto& [targetUserId, targetDeviceId] :
+             asKeyValueRange(devices)) {
+            if (!hasOlmSession(targetUserId, targetDeviceId)
+                && !d->createOlmSession(
+                    targetUserId, targetDeviceId,
+                    oneTimeKeys[targetUserId][targetDeviceId]))
+                continue;
+
+            // Noisy but nice for debugging
+//            qDebug(E2EE) << "Creating the payload for" << targetUserId
+//                         << targetDeviceId << sessionId << sessionKey.toHex();
+            usersToDevicesToContent[targetUserId][targetDeviceId] =
+                d->encryptSessionKeyEvent(keyEventJson, targetUserId,
+                                          targetDeviceId);
+        }
+        if (!usersToDevicesToContent.empty()) {
+            sendToDevices(EncryptedEvent::TypeId, usersToDevicesToContent);
+            QVector<std::tuple<QString, QString, QString>> receivedDevices;
+            receivedDevices.reserve(devices.size());
+            for (const auto& [user, device] : asKeyValueRange(devices))
+                receivedDevices.push_back(
+                    { user, device, d->curveKeyForUserDevice(user, device) });
+
+            database()->setDevicesReceivedKey(roomId, receivedDevices,
+                                              sessionId, index);
+        }
+    });
 }
 
-void Connection::saveCurrentOutboundMegolmSession(Room *room, const QOlmOutboundGroupSessionPtr& data)
+QOlmOutboundGroupSessionPtr Connection::loadCurrentOutboundMegolmSession(
+    const QString& roomId) const
 {
-    d->database->saveCurrentOutboundMegolmSession(room->id(), d->picklingMode, data);
+    return d->database->loadCurrentOutboundMegolmSession(roomId,
+                                                         d->picklingMode);
 }
 
-bool Connection::isKnownCurveKey(const QString& user, const QString& curveKey)
+void Connection::saveCurrentOutboundMegolmSession(
+    const QString& roomId, const QOlmOutboundGroupSession& session) const
 {
-    auto query = database()->prepareQuery(QStringLiteral("SELECT * FROM tracked_devices WHERE matrixId=:matrixId AND curveKey=:curveKey"));
-    query.bindValue(":matrixId", user);
-    query.bindValue(":curveKey", curveKey);
-    database()->execute(query);
-    return query.next();
+    d->database->saveCurrentOutboundMegolmSession(roomId, d->picklingMode,
+                                                  session);
 }
 
 #endif
@@ -2339,10 +2466,9 @@ void Connection::startKeyVerificationSession(const QString& deviceId)
     Q_EMIT newKeyVerificationSession(session);
 }
 
-void Connection::sendToDevice(const QString& userId, const QString& deviceId, event_ptr_tt<Event> event, bool encrypted)
+void Connection::sendToDevice(const QString& userId, const QString& deviceId,
+                              event_ptr_tt<Event> event, bool encrypted)
 {
-
-    UsersToDevicesToEvents payload;
     if (encrypted) {
         QJsonObject payloadJson = event->fullJson();
         payloadJson["recipient"] = userId;
@@ -2354,16 +2480,23 @@ void Connection::sendToDevice(const QString& userId, const QString& deviceId, ev
         senderObject["ed25519"] = QString(olmAccount()->identityKeys().ed25519);
         payloadJson["keys"] = senderObject;
 
-        const auto& u = user(userId);
-        auto cipherText = olmEncryptMessage(u, deviceId, QJsonDocument(payloadJson).toJson(QJsonDocument::Compact));
+        auto cipherText = d->olmEncryptMessage(
+            userId, deviceId,
+            QJsonDocument(payloadJson).toJson(QJsonDocument::Compact));
         QJsonObject encryptedJson;
-        encryptedJson[curveKeyForUserDevice(userId, deviceId)] = QJsonObject{{"type", cipherText.first}, {"body", QString(cipherText.second)}, {"sender", this->userId()}};
-        auto encryptedEvent = makeEvent<EncryptedEvent>(encryptedJson, olmAccount()->identityKeys().curve25519);
-        payload[userId][deviceId] = std::move(encryptedEvent);
-    } else {
-        payload[userId][deviceId] = std::move(event);
-    }
-    sendToDevices(payload[userId][deviceId]->matrixType(), payload);
+        encryptedJson[d->curveKeyForUserDevice(userId, deviceId)] =
+            QJsonObject{ { "type", cipherText.first },
+                         { "body", QString(cipherText.second) },
+                         { "sender", this->userId() } };
+        const auto& contentJson =
+            EncryptedEvent(encryptedJson,
+                           olmAccount()->identityKeys().curve25519)
+                .contentJson();
+        sendToDevices(EncryptedEvent::TypeId,
+                      { { userId, { { deviceId, contentJson } } } });
+    } else
+        sendToDevices(event->matrixType(),
+                      { { userId, { { deviceId, event->contentJson() } } } });
 }
 
 bool Connection::isVerifiedSession(const QString& megolmSessionId)
diff --git a/lib/connection.h b/lib/connection.h
index fc189ac4..b684d16b 100644
--- a/lib/connection.h
+++ b/lib/connection.h
@@ -53,7 +53,7 @@ class SendToDeviceJob;
 class SendMessageJob;
 class LeaveRoomJob;
 class Database;
-struct EncryptedFile;
+struct EncryptedFileMetadata;
 
 class QOlmAccount;
 class QOlmInboundGroupSession;
@@ -135,8 +135,7 @@ class QUOTIENT_API Connection : public QObject {
     Q_PROPERTY(bool canChangePassword READ canChangePassword NOTIFY capabilitiesLoaded)
 
 public:
-    using UsersToDevicesToEvents =
-        UnorderedMap<QString, UnorderedMap<QString, std::unique_ptr<Event>>>;
+    using UsersToDevicesToContent = QHash<QString, QHash<QString, QJsonObject>>;
 
     enum RoomVisibility {
         PublishRoom,
@@ -177,24 +176,25 @@ public:
      */
     bool hasAccountData(const QString& type) const;
 
-    /** Get a generic account data event of the given type
-     * This returns an account data event of the given type
-     * stored on the server. Direct chats map cannot be retrieved
-     * using this method _yet_; use directChats() instead.
-     */
+    //! \brief Get a generic account data event of the given type
+    //!
+    //! \return an account data event of the given type stored on the server,
+    //!         or nullptr if there's none of that type.
+    //! \note Direct chats map cannot be retrieved using this method _yet_;
+    //!       use directChats() instead.
     const EventPtr& accountData(const QString& type) const;
 
-    /** Get a generic account data event of the given type
-     * This returns an account data event of the given type
-     * stored on the server. Direct chats map cannot be retrieved
-     * using this method _yet_; use directChats() instead.
-     */
+    //! \brief Get an account data event of the given type
+    //!
+    //! \return the account data content for the given event type stored
+    //!         on the server, or a default-constructed object if there's none
+    //!         of that type.
+    //! \note Direct chats map cannot be retrieved using this method _yet_;
+    //!       use directChats() instead.
     template <typename EventT>
-    const typename EventT::content_type accountData() const
+    const EventT* accountData() const
     {
-        if (const auto& eventPtr = accountData(EventT::matrixTypeId()))
-            return eventPtr->content();
-        return {};
+        return eventCast<EventT>(accountData(EventT::TypeId));
     }
 
     /** Get account data as a JSON object
@@ -320,21 +320,33 @@ public:
     bool isLoggedIn() const;
 #ifdef Quotient_E2EE_ENABLED
     QOlmAccount* olmAccount() const;
-    Database* database();
-    bool hasOlmSession(User* user, const QString& deviceId) const;
+    Database* database() const;
+    PicklingMode picklingMode() const;
+
+    UnorderedMap<QString, QOlmInboundGroupSessionPtr> loadRoomMegolmSessions(
+        const Room* room) const;
+    void saveMegolmSession(const Room* room,
+                           const QOlmInboundGroupSession& session) const;
+    QOlmOutboundGroupSessionPtr loadCurrentOutboundMegolmSession(
+        const QString& roomId) const;
+    void saveCurrentOutboundMegolmSession(
+        const QString& roomId, const QOlmOutboundGroupSession& session) const;
+
 
-    QOlmOutboundGroupSessionPtr loadCurrentOutboundMegolmSession(Room* room);
-    void saveCurrentOutboundMegolmSession(Room *room, const QOlmOutboundGroupSessionPtr& data);
+    QString edKeyForUserDevice(const QString& user, const QString& device) const;
+    bool hasOlmSession(const QString& user, const QString& deviceId) const;
 
     /// Returns true if this megolm session comes from a verified device
     bool isVerifiedSession(const QString& megolmSessionId);
 
-    //This assumes that an olm session with (user, device) exists
-    QPair<QOlmMessage::Type, QByteArray> olmEncryptMessage(User* user, const QString& device, const QByteArray& message);
-    void createOlmSession(const QString& theirIdentityKey, const QString& theirOneTimeKey);
+    void sendSessionKeyToDevices(const QString& roomId,
+                                 const QByteArray& sessionId,
+                                 const QByteArray& sessionKey,
+                                 const QMultiHash<QString, QString>& devices,
+                                 int index);
 
-    UnorderedMap<QString, QOlmInboundGroupSessionPtr> loadRoomMegolmSessions(Room* room);
-    void saveMegolmSession(Room* room, QOlmInboundGroupSession* session);
+    QJsonObject decryptNotification(const QJsonObject &notification);
+    QStringList devicesForUser(const QString& userId) const;
 #endif // Quotient_E2EE_ENABLED
     Q_INVOKABLE Quotient::SyncJob* syncJob() const;
     Q_INVOKABLE int millisToReconnect() const;
@@ -607,7 +619,8 @@ public Q_SLOTS:
                                   const QString& localFilename = {});
 
 #ifdef Quotient_E2EE_ENABLED
-    DownloadFileJob* downloadFile(const QUrl& url, const EncryptedFile& file,
+    DownloadFileJob* downloadFile(const QUrl& url,
+                                  const EncryptedFileMetadata& fileMetadata,
                                   const QString& localFilename = {});
 #endif
     /**
@@ -687,7 +700,7 @@ public Q_SLOTS:
     ForgetRoomJob* forgetRoom(const QString& id);
 
     SendToDeviceJob* sendToDevices(const QString& eventType,
-                                   const UsersToDevicesToEvents& eventsMap);
+                                   const UsersToDevicesToContent& contents);
 
     /** \deprecated This method is experimental and may be removed any time */
     SendMessageJob* sendMessage(const QString& roomId, const RoomEvent& event);
@@ -699,13 +712,6 @@ public Q_SLOTS:
 
 #ifdef Quotient_E2EE_ENABLED
     void encryptionUpdate(Room *room);
-    PicklingMode picklingMode() const;
-    QJsonObject decryptNotification(const QJsonObject &notification);
-
-    QStringList devicesForUser(User* user) const;
-    QString curveKeyForUserDevice(const QString &user, const QString& device) const;
-    QString edKeyForUserDevice(const QString& user, const QString& device) const;
-    bool isKnownCurveKey(const QString& user, const QString& curveKey);
 #endif
 
 Q_SIGNALS:
diff --git a/lib/converters.cpp b/lib/converters.cpp
index 444ca4f6..b0e3a4b6 100644
--- a/lib/converters.cpp
+++ b/lib/converters.cpp
@@ -2,9 +2,23 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
 
 #include "converters.h"
+#include "logging.h"
 
 #include <QtCore/QVariant>
 
+void Quotient::_impl::warnUnknownEnumValue(const QString& stringValue,
+                                           const char* enumTypeName)
+{
+    qWarning(EVENTS).noquote()
+        << "Unknown" << enumTypeName << "value:" << stringValue;
+}
+
+void Quotient::_impl::reportEnumOutOfBounds(uint32_t v, const char* enumTypeName)
+{
+    qCritical(MAIN).noquote()
+        << "Value" << v << "is out of bounds for enumeration" << enumTypeName;
+}
+
 QJsonValue Quotient::JsonConverter<QVariant>::dump(const QVariant& v)
 {
     return QJsonValue::fromVariant(v);
diff --git a/lib/converters.h b/lib/converters.h
index 515c96fd..688f7bbd 100644
--- a/lib/converters.h
+++ b/lib/converters.h
@@ -16,6 +16,7 @@
 
 #include <type_traits>
 #include <vector>
+#include <variant>
 
 class QVariant;
 
@@ -27,23 +28,19 @@ struct JsonObjectConverter {
     static void fillFrom(const QJsonObject&, T&) = delete;
 };
 
-namespace _impl {
-    template <typename T, typename = void>
-    struct JsonExporter {
-        static QJsonObject dump(const T& data)
-        {
-            QJsonObject jo;
-            JsonObjectConverter<T>::dumpTo(jo, data);
-            return jo;
-        }
-    };
+template <typename PodT, typename JsonT>
+PodT fromJson(const JsonT&);
 
-    template <typename T>
-    struct JsonExporter<
-        T, std::enable_if_t<std::is_invocable_v<decltype(&T::toJson), T>>> {
-        static auto dump(const T& data) { return data.toJson(); }
-    };
-}
+template <typename T>
+struct JsonObjectUnpacker {
+    // By default, revert to fromJson() so that one could provide a single
+    // fromJson<T, QJsonObject> specialisation instead of specialising
+    // the entire JsonConverter; if a different type of JSON value is needed
+    // (e.g., an array), specialising JsonConverter is inevitable
+    static T load(QJsonValueRef jvr) { return fromJson<T>(QJsonValue(jvr)); }
+    static T load(const QJsonValue& jv) { return fromJson<T>(jv.toObject()); }
+    static T load(const QJsonDocument& jd) { return fromJson<T>(jd.object()); }
+};
 
 //! \brief The switchboard for extra conversion algorithms behind from/toJson
 //!
@@ -61,13 +58,24 @@ namespace _impl {
 //! that they are not supported and it's not feasible to support those by means
 //! of overloading toJson() and specialising fromJson().
 template <typename T>
-struct JsonConverter : _impl::JsonExporter<T> {
+struct JsonConverter : JsonObjectUnpacker<T> {
     // Unfortunately, if constexpr doesn't work with dump() and T::toJson
     // because trying to check invocability of T::toJson hits a hard
     // (non-SFINAE) compilation error if the member is not there. Hence a bit
     // more verbose SFINAE construct in _impl::JsonExporter.
+    static auto dump(const T& data)
+    {
+        if constexpr (requires() { data.toJson(); })
+            return data.toJson();
+        else {
+            QJsonObject jo;
+            JsonObjectConverter<T>::dumpTo(jo, data);
+            return jo;
+        }
+    }
 
-    static T doLoad(const QJsonObject& jo)
+    using JsonObjectUnpacker<T>::load;
+    static T load(const QJsonObject& jo)
     {
         // 'else' below are required to suppress code generation for unused
         // branches - 'return' is not enough
@@ -81,66 +89,143 @@ struct JsonConverter : _impl::JsonExporter<T> {
             return pod;
         }
     }
-    static T load(const QJsonValue& jv) { return doLoad(jv.toObject()); }
-    static T load(const QJsonDocument& jd) { return doLoad(jd.object()); }
 };
 
-template <typename T,
-          typename = std::enable_if_t<!std::is_constructible_v<QJsonValue, T>>>
+template <typename T>
 inline auto toJson(const T& pod)
 // -> can return anything from which QJsonValue or, in some cases, QJsonDocument
 //    is constructible
 {
-    return JsonConverter<T>::dump(pod);
+    if constexpr (std::is_constructible_v<QJsonValue, T>)
+        return pod; // No-op if QJsonValue can be directly constructed
+    else
+        return JsonConverter<T>::dump(pod);
 }
 
-inline auto toJson(const QJsonObject& jo) { return jo; }
-inline auto toJson(const QJsonValue& jv) { return jv; }
-
 template <typename T>
 inline void fillJson(QJsonObject& json, const T& data)
 {
     JsonObjectConverter<T>::dumpTo(json, data);
 }
 
-template <typename T>
-inline T fromJson(const QJsonValue& jv)
+template <typename PodT, typename JsonT>
+inline PodT fromJson(const JsonT& json)
 {
-    return JsonConverter<T>::load(jv);
+    // JsonT here can be whatever the respective JsonConverter specialisation
+    // accepts but by default it's QJsonValue, QJsonDocument, or QJsonObject
+    return JsonConverter<PodT>::load(json);
 }
 
-template<>
-inline QJsonValue fromJson(const QJsonValue& jv) { return jv; }
+// Convenience fromJson() overload that deduces PodT instead of requiring
+// the coder to explicitly type it. It still enforces the
+// overwrite-everything semantics of fromJson(), unlike fillFromJson()
+
+template <typename JsonT, typename PodT>
+inline void fromJson(const JsonT& json, PodT& pod)
+{
+    pod = fromJson<PodT>(json);
+}
 
 template <typename T>
-inline T fromJson(const QJsonDocument& jd)
+inline void fillFromJson(const QJsonValue& jv, T& pod)
 {
-    return JsonConverter<T>::load(jd);
+    if constexpr (requires() { JsonObjectConverter<T>::fillFrom({}, pod); }) {
+        JsonObjectConverter<T>::fillFrom(jv.toObject(), pod);
+        return;
+    } else if (!jv.isUndefined())
+        pod = fromJson<T>(jv);
 }
 
-// Convenience fromJson() overloads that deduce T instead of requiring
-// the coder to explicitly type it. They still enforce the
-// overwrite-everything semantics of fromJson(), unlike fillFromJson()
+namespace _impl {
+    void warnUnknownEnumValue(const QString& stringValue,
+                              const char* enumTypeName);
+    void reportEnumOutOfBounds(uint32_t v, const char* enumTypeName);
+}
 
-template <typename T>
-inline void fromJson(const QJsonValue& jv, T& pod)
+//! \brief Facility string-to-enum converter
+//!
+//! This is to simplify enum loading from JSON - just specialise
+//! Quotient::fromJson() and call this function from it, passing (aside from
+//! the JSON value for the enum - that must be a string, not an int) any
+//! iterable container of string'y values (const char*, QLatin1String, etc.)
+//! matching respective enum values, 0-based.
+//! \sa enumToJsonString
+template <typename EnumT, typename EnumStringValuesT>
+EnumT enumFromJsonString(const QString& s, const EnumStringValuesT& enumValues,
+                         EnumT defaultValue)
 {
-    pod = jv.isUndefined() ? T() : fromJson<T>(jv);
+    static_assert(std::is_unsigned_v<std::underlying_type_t<EnumT>>);
+    if (const auto it = std::find(cbegin(enumValues), cend(enumValues), s);
+        it != cend(enumValues))
+        return EnumT(it - cbegin(enumValues));
+
+    if (!s.isEmpty())
+        _impl::warnUnknownEnumValue(s, qt_getEnumName(EnumT()));
+    return defaultValue;
 }
 
-template <typename T>
-inline void fromJson(const QJsonDocument& jd, T& pod)
+//! \brief Facility enum-to-string converter
+//!
+//! This does the same as enumFromJsonString, the other way around.
+//! \note The source enumeration must not have gaps in values, or \p enumValues
+//!       has to match those gaps (i.e., if the source enumeration is defined
+//!       as <tt>{ Value1 = 1, Value2 = 3, Value3 = 5 }</tt> then \p enumValues
+//!       should be defined as <tt>{ "", "Value1", "", "Value2", "", "Value3"
+//!       }</tt> (mind the gap at value 0, in particular).
+//! \sa enumFromJsonString
+template <typename EnumT, typename EnumStringValuesT>
+QString enumToJsonString(EnumT v, const EnumStringValuesT& enumValues)
 {
-    pod = fromJson<T>(jd);
+    static_assert(std::is_unsigned_v<std::underlying_type_t<EnumT>>);
+    if (v < size(enumValues))
+        return enumValues[v];
+
+    _impl::reportEnumOutOfBounds(static_cast<uint32_t>(v),
+                                 qt_getEnumName(EnumT()));
+    Q_ASSERT(false);
+    return {};
 }
 
-template <typename T>
-inline void fillFromJson(const QJsonValue& jv, T& pod)
+//! \brief Facility converter for flags
+//!
+//! This is very similar to enumFromJsonString, except that the target
+//! enumeration is assumed to be of a 'flag' kind - i.e. its values must be
+//! a power-of-two sequence starting from 1, without gaps, so exactly 1,2,4,8,16
+//! and so on.
+//! \note Unlike enumFromJsonString, the values start from 1 and not from 0,
+//!       with 0 being used for an invalid value by default.
+//! \note This function does not support flag combinations.
+//! \sa QUO_DECLARE_FLAGS, QUO_DECLARE_FLAGS_NS
+template <typename FlagT, typename FlagStringValuesT>
+FlagT flagFromJsonString(const QString& s, const FlagStringValuesT& flagValues,
+                         FlagT defaultValue = FlagT(0U))
 {
-    if (jv.isObject())
-        JsonObjectConverter<T>::fillFrom(jv.toObject(), pod);
-    else if (!jv.isUndefined())
-        pod = fromJson<T>(jv);
+    // Enums based on signed integers don't make much sense for flag types
+    static_assert(std::is_unsigned_v<std::underlying_type_t<FlagT>>);
+    if (const auto it = std::find(cbegin(flagValues), cend(flagValues), s);
+        it != cend(flagValues))
+        return FlagT(1U << (it - cbegin(flagValues)));
+
+    if (!s.isEmpty())
+        _impl::warnUnknownEnumValue(s, qt_getEnumName(FlagT()));
+    return defaultValue;
+}
+
+template <typename FlagT, typename FlagStringValuesT>
+QString flagToJsonString(FlagT v, const FlagStringValuesT& flagValues)
+{
+    static_assert(std::is_unsigned_v<std::underlying_type_t<FlagT>>);
+    if (const auto offset =
+            qCountTrailingZeroBits(std::underlying_type_t<FlagT>(v));
+        offset < size(flagValues)) //
+    {
+        return flagValues[offset];
+    }
+
+    _impl::reportEnumOutOfBounds(static_cast<uint32_t>(v),
+                                 qt_getEnumName(FlagT()));
+    Q_ASSERT(false);
+    return {};
 }
 
 // JsonConverter<> specialisations
@@ -163,6 +248,14 @@ inline qint64 fromJson(const QJsonValue& jv) { return qint64(jv.toDouble()); }
 template <>
 inline QString fromJson(const QJsonValue& jv) { return jv.toString(); }
 
+//! Use fromJson<QString> and use toLatin1()/toUtf8()/... to make QByteArray
+//!
+//! QJsonValue can only convert to QString and there's ambiguity whether
+//! conversion to QByteArray should use (fast but very limited) toLatin1() or
+//! (all encompassing and conforming to the JSON spec but slow) toUtf8().
+template <>
+inline QByteArray fromJson(const QJsonValue& jv) = delete;
+
 template <>
 inline QJsonArray fromJson(const QJsonValue& jv) { return jv.toArray(); }
 
@@ -179,15 +272,7 @@ inline QDateTime fromJson(const QJsonValue& jv)
     return QDateTime::fromMSecsSinceEpoch(fromJson<qint64>(jv), Qt::UTC);
 }
 
-inline QJsonValue toJson(const QDate& val) {
-    return toJson(
-#if QT_VERSION < QT_VERSION_CHECK(5, 14, 0)
-        QDateTime(val)
-#else
-        val.startOfDay()
-#endif
-    );
-}
+inline QJsonValue toJson(const QDate& val) { return toJson(val.startOfDay()); }
 template <>
 inline QDate fromJson(const QJsonValue& jv)
 {
@@ -216,6 +301,26 @@ struct QUOTIENT_API JsonConverter<QVariant> {
     static QVariant load(const QJsonValue& jv);
 };
 
+template <typename... Ts>
+inline QJsonValue toJson(const std::variant<Ts...>& v)
+{
+    // std::visit requires all overloads to return the same type - and
+    // QJsonValue is a perfect candidate for that same type (assuming that
+    // variants never occur on the top level in Matrix API)
+    return std::visit(
+        [](const auto& value) { return QJsonValue { toJson(value) }; }, v);
+}
+
+template <typename T>
+struct JsonConverter<std::variant<QString, T>> {
+    static std::variant<QString, T> load(const QJsonValue& jv)
+    {
+        if (jv.isString())
+            return fromJson<QString>(jv);
+        return fromJson<T>(jv);
+    }
+};
+
 template <typename T>
 struct JsonConverter<Omittable<T>> {
     static QJsonValue dump(const Omittable<T>& from)
@@ -414,4 +519,20 @@ inline void addParam(ContT& container, const QString& key, ValT&& value)
     _impl::AddNode<std::decay_t<ValT>, Force>::impl(container, key,
                                                     std::forward<ValT>(value));
 }
+
+// This is a facility function to convert camelCase method/variable names
+// used throughout Quotient to snake_case JSON keys - see usage in
+// single_key_value.h and event.h (DEFINE_CONTENT_GETTER macro).
+inline auto toSnakeCase(QLatin1String s)
+{
+    QString result { s };
+    for (auto it = result.begin(); it != result.end(); ++it)
+        if (it->isUpper()) {
+            const auto offset = static_cast<int>(it - result.begin());
+            result.insert(offset, '_'); // NB: invalidates iterators
+            it = result.begin() + offset + 1;
+            *it = it->toLower();
+        }
+    return result;
+}
 } // namespace Quotient
diff --git a/lib/csapi/account-data.cpp b/lib/csapi/account-data.cpp
index 09fc8d40..8c71f6c5 100644
--- a/lib/csapi/account-data.cpp
+++ b/lib/csapi/account-data.cpp
@@ -9,23 +9,23 @@ using namespace Quotient;
 SetAccountDataJob::SetAccountDataJob(const QString& userId, const QString& type,
                                      const QJsonObject& content)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetAccountDataJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/account_data/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/account_data/",
                        type))
 {
-    setRequestData(RequestData(toJson(content)));
+    setRequestData({ toJson(content) });
 }
 
 QUrl GetAccountDataJob::makeRequestUrl(QUrl baseUrl, const QString& userId,
                                        const QString& type)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/user/",
+                                   makePath("/_matrix/client/v3", "/user/",
                                             userId, "/account_data/", type));
 }
 
 GetAccountDataJob::GetAccountDataJob(const QString& userId, const QString& type)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetAccountDataJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/account_data/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/account_data/",
                        type))
 {}
 
@@ -34,10 +34,10 @@ SetAccountDataPerRoomJob::SetAccountDataPerRoomJob(const QString& userId,
                                                    const QString& type,
                                                    const QJsonObject& content)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetAccountDataPerRoomJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/rooms/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/rooms/",
                        roomId, "/account_data/", type))
 {
-    setRequestData(RequestData(toJson(content)));
+    setRequestData({ toJson(content) });
 }
 
 QUrl GetAccountDataPerRoomJob::makeRequestUrl(QUrl baseUrl,
@@ -46,7 +46,7 @@ QUrl GetAccountDataPerRoomJob::makeRequestUrl(QUrl baseUrl,
                                               const QString& type)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/user/",
+                                   makePath("/_matrix/client/v3", "/user/",
                                             userId, "/rooms/", roomId,
                                             "/account_data/", type));
 }
@@ -55,6 +55,6 @@ GetAccountDataPerRoomJob::GetAccountDataPerRoomJob(const QString& userId,
                                                    const QString& roomId,
                                                    const QString& type)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetAccountDataPerRoomJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/rooms/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/rooms/",
                        roomId, "/account_data/", type))
 {}
diff --git a/lib/csapi/admin.cpp b/lib/csapi/admin.cpp
index 81dd0624..322212db 100644
--- a/lib/csapi/admin.cpp
+++ b/lib/csapi/admin.cpp
@@ -9,11 +9,11 @@ using namespace Quotient;
 QUrl GetWhoIsJob::makeRequestUrl(QUrl baseUrl, const QString& userId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/admin/whois/", userId));
 }
 
 GetWhoIsJob::GetWhoIsJob(const QString& userId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetWhoIsJob"),
-              makePath("/_matrix/client/r0", "/admin/whois/", userId))
+              makePath("/_matrix/client/v3", "/admin/whois/", userId))
 {}
diff --git a/lib/csapi/administrative_contact.cpp b/lib/csapi/administrative_contact.cpp
index 589c9fc1..aa55d934 100644
--- a/lib/csapi/administrative_contact.cpp
+++ b/lib/csapi/administrative_contact.cpp
@@ -9,59 +9,59 @@ using namespace Quotient;
 QUrl GetAccount3PIDsJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/account/3pid"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/account/3pid"));
 }
 
 GetAccount3PIDsJob::GetAccount3PIDsJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetAccount3PIDsJob"),
-              makePath("/_matrix/client/r0", "/account/3pid"))
+              makePath("/_matrix/client/v3", "/account/3pid"))
 {}
 
 Post3PIDsJob::Post3PIDsJob(const ThreePidCredentials& threePidCreds)
     : BaseJob(HttpVerb::Post, QStringLiteral("Post3PIDsJob"),
-              makePath("/_matrix/client/r0", "/account/3pid"))
+              makePath("/_matrix/client/v3", "/account/3pid"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("three_pid_creds"), threePidCreds);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("three_pid_creds"), threePidCreds);
+    setRequestData({ _dataJson });
 }
 
 Add3PIDJob::Add3PIDJob(const QString& clientSecret, const QString& sid,
                        const Omittable<AuthenticationData>& auth)
     : BaseJob(HttpVerb::Post, QStringLiteral("Add3PIDJob"),
-              makePath("/_matrix/client/r0", "/account/3pid/add"))
+              makePath("/_matrix/client/v3", "/account/3pid/add"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("auth"), auth);
-    addParam<>(_data, QStringLiteral("client_secret"), clientSecret);
-    addParam<>(_data, QStringLiteral("sid"), sid);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    addParam<>(_dataJson, QStringLiteral("client_secret"), clientSecret);
+    addParam<>(_dataJson, QStringLiteral("sid"), sid);
+    setRequestData({ _dataJson });
 }
 
 Bind3PIDJob::Bind3PIDJob(const QString& clientSecret, const QString& idServer,
                          const QString& idAccessToken, const QString& sid)
     : BaseJob(HttpVerb::Post, QStringLiteral("Bind3PIDJob"),
-              makePath("/_matrix/client/r0", "/account/3pid/bind"))
+              makePath("/_matrix/client/v3", "/account/3pid/bind"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("client_secret"), clientSecret);
-    addParam<>(_data, QStringLiteral("id_server"), idServer);
-    addParam<>(_data, QStringLiteral("id_access_token"), idAccessToken);
-    addParam<>(_data, QStringLiteral("sid"), sid);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("client_secret"), clientSecret);
+    addParam<>(_dataJson, QStringLiteral("id_server"), idServer);
+    addParam<>(_dataJson, QStringLiteral("id_access_token"), idAccessToken);
+    addParam<>(_dataJson, QStringLiteral("sid"), sid);
+    setRequestData({ _dataJson });
 }
 
 Delete3pidFromAccountJob::Delete3pidFromAccountJob(const QString& medium,
                                                    const QString& address,
                                                    const QString& idServer)
     : BaseJob(HttpVerb::Post, QStringLiteral("Delete3pidFromAccountJob"),
-              makePath("/_matrix/client/r0", "/account/3pid/delete"))
+              makePath("/_matrix/client/v3", "/account/3pid/delete"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("id_server"), idServer);
-    addParam<>(_data, QStringLiteral("medium"), medium);
-    addParam<>(_data, QStringLiteral("address"), address);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("id_server"), idServer);
+    addParam<>(_dataJson, QStringLiteral("medium"), medium);
+    addParam<>(_dataJson, QStringLiteral("address"), address);
+    setRequestData({ _dataJson });
     addExpectedKey("id_server_unbind_result");
 }
 
@@ -69,32 +69,32 @@ Unbind3pidFromAccountJob::Unbind3pidFromAccountJob(const QString& medium,
                                                    const QString& address,
                                                    const QString& idServer)
     : BaseJob(HttpVerb::Post, QStringLiteral("Unbind3pidFromAccountJob"),
-              makePath("/_matrix/client/r0", "/account/3pid/unbind"))
+              makePath("/_matrix/client/v3", "/account/3pid/unbind"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("id_server"), idServer);
-    addParam<>(_data, QStringLiteral("medium"), medium);
-    addParam<>(_data, QStringLiteral("address"), address);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("id_server"), idServer);
+    addParam<>(_dataJson, QStringLiteral("medium"), medium);
+    addParam<>(_dataJson, QStringLiteral("address"), address);
+    setRequestData({ _dataJson });
     addExpectedKey("id_server_unbind_result");
 }
 
 RequestTokenTo3PIDEmailJob::RequestTokenTo3PIDEmailJob(
     const EmailValidationData& body)
     : BaseJob(HttpVerb::Post, QStringLiteral("RequestTokenTo3PIDEmailJob"),
-              makePath("/_matrix/client/r0",
+              makePath("/_matrix/client/v3",
                        "/account/3pid/email/requestToken"),
               false)
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
 
 RequestTokenTo3PIDMSISDNJob::RequestTokenTo3PIDMSISDNJob(
     const MsisdnValidationData& body)
     : BaseJob(HttpVerb::Post, QStringLiteral("RequestTokenTo3PIDMSISDNJob"),
-              makePath("/_matrix/client/r0",
+              makePath("/_matrix/client/v3",
                        "/account/3pid/msisdn/requestToken"),
               false)
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
diff --git a/lib/csapi/administrative_contact.h b/lib/csapi/administrative_contact.h
index e636b12a..27334850 100644
--- a/lib/csapi/administrative_contact.h
+++ b/lib/csapi/administrative_contact.h
@@ -128,6 +128,22 @@ public:
      *   The third party credentials to associate with the account.
      */
     explicit Post3PIDsJob(const ThreePidCredentials& threePidCreds);
+
+    // Result properties
+
+    /// An optional field containing a URL where the client must
+    /// submit the validation token to, with identical parameters
+    /// to the Identity Service API's `POST
+    /// /validate/email/submitToken` endpoint (without the requirement
+    /// for an access token). The homeserver must send this token to the
+    /// user (if applicable), who should then be prompted to provide it
+    /// to the client.
+    ///
+    /// If this field is not present, the client can assume that
+    /// verification will happen without the client's involvement
+    /// provided the homeserver advertises this specification version
+    /// in the `/versions` response (ie: r0.5.0).
+    QUrl submitUrl() const { return loadFromJson<QUrl>("submit_url"_ls); }
 };
 
 template <>
@@ -235,7 +251,7 @@ public:
 
     /// An indicator as to whether or not the homeserver was able to unbind
     /// the 3PID from the identity server. `success` indicates that the
-    /// indentity server has unbound the identifier whereas `no-support`
+    /// identity server has unbound the identifier whereas `no-support`
     /// indicates that the identity server refuses to support the request
     /// or the homeserver was not able to determine an identity server to
     /// unbind from.
@@ -295,7 +311,7 @@ public:
  * be used to request validation tokens when adding an email address to an
  * account. This API's parameters and response are identical to that of
  * the
- * [`/register/email/requestToken`](/client-server-api/#post_matrixclientr0registeremailrequesttoken)
+ * [`/register/email/requestToken`](/client-server-api/#post_matrixclientv3registeremailrequesttoken)
  * endpoint. The homeserver should validate
  * the email itself, either by sending a validation email itself or by using
  * a service it has control over.
@@ -311,7 +327,7 @@ public:
      *   be used to request validation tokens when adding an email address to an
      *   account. This API's parameters and response are identical to that of
      *   the
-     * [`/register/email/requestToken`](/client-server-api/#post_matrixclientr0registeremailrequesttoken)
+     * [`/register/email/requestToken`](/client-server-api/#post_matrixclientv3registeremailrequesttoken)
      *   endpoint. The homeserver should validate
      *   the email itself, either by sending a validation email itself or by
      * using a service it has control over.
@@ -337,7 +353,7 @@ public:
  * be used to request validation tokens when adding a phone number to an
  * account. This API's parameters and response are identical to that of
  * the
- * [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientr0registermsisdnrequesttoken)
+ * [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientv3registermsisdnrequesttoken)
  * endpoint. The homeserver should validate
  * the phone number itself, either by sending a validation message itself or by
  * using a service it has control over.
@@ -353,7 +369,7 @@ public:
      *   be used to request validation tokens when adding a phone number to an
      *   account. This API's parameters and response are identical to that of
      *   the
-     * [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientr0registermsisdnrequesttoken)
+     * [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientv3registermsisdnrequesttoken)
      *   endpoint. The homeserver should validate
      *   the phone number itself, either by sending a validation message itself
      * or by using a service it has control over.
diff --git a/lib/csapi/appservice_room_directory.cpp b/lib/csapi/appservice_room_directory.cpp
index 40d784c6..dff7e032 100644
--- a/lib/csapi/appservice_room_directory.cpp
+++ b/lib/csapi/appservice_room_directory.cpp
@@ -6,14 +6,16 @@
 
 using namespace Quotient;
 
-UpdateAppserviceRoomDirectoryVisibilityJob::UpdateAppserviceRoomDirectoryVisibilityJob(
-    const QString& networkId, const QString& roomId, const QString& visibility)
+UpdateAppserviceRoomDirectoryVisibilityJob::
+    UpdateAppserviceRoomDirectoryVisibilityJob(const QString& networkId,
+                                               const QString& roomId,
+                                               const QString& visibility)
     : BaseJob(HttpVerb::Put,
               QStringLiteral("UpdateAppserviceRoomDirectoryVisibilityJob"),
-              makePath("/_matrix/client/r0", "/directory/list/appservice/",
+              makePath("/_matrix/client/v3", "/directory/list/appservice/",
                        networkId, "/", roomId))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("visibility"), visibility);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("visibility"), visibility);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/appservice_room_directory.h b/lib/csapi/appservice_room_directory.h
index 6b2801ca..d6268979 100644
--- a/lib/csapi/appservice_room_directory.h
+++ b/lib/csapi/appservice_room_directory.h
@@ -21,8 +21,7 @@ namespace Quotient {
  * instead of a typical client's access_token. This API cannot be invoked by
  * users who are not identified as application services.
  */
-class QUOTIENT_API UpdateAppserviceRoomDirectoryVisibilityJob
-    : public BaseJob {
+class QUOTIENT_API UpdateAppserviceRoomDirectoryVisibilityJob : public BaseJob {
 public:
     /*! \brief Updates a room's visibility in the application service's room
      * directory.
diff --git a/lib/csapi/banning.cpp b/lib/csapi/banning.cpp
index 472128bb..e04075b7 100644
--- a/lib/csapi/banning.cpp
+++ b/lib/csapi/banning.cpp
@@ -9,21 +9,21 @@ using namespace Quotient;
 BanJob::BanJob(const QString& roomId, const QString& userId,
                const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("BanJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/ban"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/ban"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("user_id"), userId);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("user_id"), userId);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
 
 UnbanJob::UnbanJob(const QString& roomId, const QString& userId,
                    const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("UnbanJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/unban"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/unban"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("user_id"), userId);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("user_id"), userId);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/capabilities.cpp b/lib/csapi/capabilities.cpp
index bc21e462..ca2a543f 100644
--- a/lib/csapi/capabilities.cpp
+++ b/lib/csapi/capabilities.cpp
@@ -9,12 +9,12 @@ using namespace Quotient;
 QUrl GetCapabilitiesJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/capabilities"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/capabilities"));
 }
 
 GetCapabilitiesJob::GetCapabilitiesJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetCapabilitiesJob"),
-              makePath("/_matrix/client/r0", "/capabilities"))
+              makePath("/_matrix/client/v3", "/capabilities"))
 {
     addExpectedKey("capabilities");
 }
diff --git a/lib/csapi/content-repo.cpp b/lib/csapi/content-repo.cpp
index 6d1e38b6..6f6738af 100644
--- a/lib/csapi/content-repo.cpp
+++ b/lib/csapi/content-repo.cpp
@@ -16,11 +16,11 @@ auto queryToUploadContent(const QString& filename)
 UploadContentJob::UploadContentJob(QIODevice* content, const QString& filename,
                                    const QString& contentType)
     : BaseJob(HttpVerb::Post, QStringLiteral("UploadContentJob"),
-              makePath("/_matrix/media/r0", "/upload"),
+              makePath("/_matrix/media/v3", "/upload"),
               queryToUploadContent(filename))
 {
     setRequestHeader("Content-Type", contentType.toLatin1());
-    setRequestData(RequestData(content));
+    setRequestData({ content });
     addExpectedKey("content_uri");
 }
 
@@ -35,7 +35,7 @@ QUrl GetContentJob::makeRequestUrl(QUrl baseUrl, const QString& serverName,
                                    const QString& mediaId, bool allowRemote)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/media/r0", "/download/",
+                                   makePath("/_matrix/media/v3", "/download/",
                                             serverName, "/", mediaId),
                                    queryToGetContent(allowRemote));
 }
@@ -43,7 +43,7 @@ QUrl GetContentJob::makeRequestUrl(QUrl baseUrl, const QString& serverName,
 GetContentJob::GetContentJob(const QString& serverName, const QString& mediaId,
                              bool allowRemote)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetContentJob"),
-              makePath("/_matrix/media/r0", "/download/", serverName, "/",
+              makePath("/_matrix/media/v3", "/download/", serverName, "/",
                        mediaId),
               queryToGetContent(allowRemote), {}, false)
 {
@@ -64,7 +64,7 @@ QUrl GetContentOverrideNameJob::makeRequestUrl(QUrl baseUrl,
                                                bool allowRemote)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/media/r0", "/download/",
+                                   makePath("/_matrix/media/v3", "/download/",
                                             serverName, "/", mediaId, "/",
                                             fileName),
                                    queryToGetContentOverrideName(allowRemote));
@@ -75,7 +75,7 @@ GetContentOverrideNameJob::GetContentOverrideNameJob(const QString& serverName,
                                                      const QString& fileName,
                                                      bool allowRemote)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetContentOverrideNameJob"),
-              makePath("/_matrix/media/r0", "/download/", serverName, "/",
+              makePath("/_matrix/media/v3", "/download/", serverName, "/",
                        mediaId, "/", fileName),
               queryToGetContentOverrideName(allowRemote), {}, false)
 {
@@ -101,16 +101,17 @@ QUrl GetContentThumbnailJob::makeRequestUrl(QUrl baseUrl,
 {
     return BaseJob::makeRequestUrl(
         std::move(baseUrl),
-        makePath("/_matrix/media/r0", "/thumbnail/", serverName, "/", mediaId),
+        makePath("/_matrix/media/v3", "/thumbnail/", serverName, "/", mediaId),
         queryToGetContentThumbnail(width, height, method, allowRemote));
 }
 
 GetContentThumbnailJob::GetContentThumbnailJob(const QString& serverName,
-                                               const QString& mediaId, int width,
-                                               int height, const QString& method,
+                                               const QString& mediaId,
+                                               int width, int height,
+                                               const QString& method,
                                                bool allowRemote)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetContentThumbnailJob"),
-              makePath("/_matrix/media/r0", "/thumbnail/", serverName, "/",
+              makePath("/_matrix/media/v3", "/thumbnail/", serverName, "/",
                        mediaId),
               queryToGetContentThumbnail(width, height, method, allowRemote),
               {}, false)
@@ -130,24 +131,24 @@ QUrl GetUrlPreviewJob::makeRequestUrl(QUrl baseUrl, const QUrl& url,
                                       Omittable<qint64> ts)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/media/r0",
+                                   makePath("/_matrix/media/v3",
                                             "/preview_url"),
                                    queryToGetUrlPreview(url, ts));
 }
 
 GetUrlPreviewJob::GetUrlPreviewJob(const QUrl& url, Omittable<qint64> ts)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetUrlPreviewJob"),
-              makePath("/_matrix/media/r0", "/preview_url"),
+              makePath("/_matrix/media/v3", "/preview_url"),
               queryToGetUrlPreview(url, ts))
 {}
 
 QUrl GetConfigJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/media/r0", "/config"));
+                                   makePath("/_matrix/media/v3", "/config"));
 }
 
 GetConfigJob::GetConfigJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetConfigJob"),
-              makePath("/_matrix/media/r0", "/config"))
+              makePath("/_matrix/media/v3", "/config"))
 {}
diff --git a/lib/csapi/content-repo.h b/lib/csapi/content-repo.h
index 511db985..2ba66a35 100644
--- a/lib/csapi/content-repo.h
+++ b/lib/csapi/content-repo.h
@@ -162,7 +162,8 @@ public:
      *
      * \param method
      *   The desired resizing method. See the
-     * [Thumbnails](/client-server-api/#thumbnails) section for more information.
+     * [Thumbnails](/client-server-api/#thumbnails) section for more
+     * information.
      *
      * \param allowRemote
      *   Indicates to the server that it should not attempt to fetch
diff --git a/lib/csapi/create_room.cpp b/lib/csapi/create_room.cpp
index 9aaef87f..afae80af 100644
--- a/lib/csapi/create_room.cpp
+++ b/lib/csapi/create_room.cpp
@@ -16,24 +16,26 @@ CreateRoomJob::CreateRoomJob(const QString& visibility,
                              const QString& preset, Omittable<bool> isDirect,
                              const QJsonObject& powerLevelContentOverride)
     : BaseJob(HttpVerb::Post, QStringLiteral("CreateRoomJob"),
-              makePath("/_matrix/client/r0", "/createRoom"))
+              makePath("/_matrix/client/v3", "/createRoom"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("visibility"), visibility);
-    addParam<IfNotEmpty>(_data, QStringLiteral("room_alias_name"),
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("visibility"), visibility);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("room_alias_name"),
                          roomAliasName);
-    addParam<IfNotEmpty>(_data, QStringLiteral("name"), name);
-    addParam<IfNotEmpty>(_data, QStringLiteral("topic"), topic);
-    addParam<IfNotEmpty>(_data, QStringLiteral("invite"), invite);
-    addParam<IfNotEmpty>(_data, QStringLiteral("invite_3pid"), invite3pid);
-    addParam<IfNotEmpty>(_data, QStringLiteral("room_version"), roomVersion);
-    addParam<IfNotEmpty>(_data, QStringLiteral("creation_content"),
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("name"), name);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("topic"), topic);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("invite"), invite);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("invite_3pid"), invite3pid);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("room_version"), roomVersion);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("creation_content"),
                          creationContent);
-    addParam<IfNotEmpty>(_data, QStringLiteral("initial_state"), initialState);
-    addParam<IfNotEmpty>(_data, QStringLiteral("preset"), preset);
-    addParam<IfNotEmpty>(_data, QStringLiteral("is_direct"), isDirect);
-    addParam<IfNotEmpty>(_data, QStringLiteral("power_level_content_override"),
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("initial_state"),
+                         initialState);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("preset"), preset);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("is_direct"), isDirect);
+    addParam<IfNotEmpty>(_dataJson,
+                         QStringLiteral("power_level_content_override"),
                          powerLevelContentOverride);
-    setRequestData(std::move(_data));
+    setRequestData({ _dataJson });
     addExpectedKey("room_id");
 }
diff --git a/lib/csapi/create_room.h b/lib/csapi/create_room.h
index 7d566057..336b9767 100644
--- a/lib/csapi/create_room.h
+++ b/lib/csapi/create_room.h
@@ -26,16 +26,18 @@ namespace Quotient {
  *    (and not other members) permission to send state events. Overridden
  *    by the `power_level_content_override` parameter.
  *
- * 4. Events set by the `preset`. Currently these are the `m.room.join_rules`,
+ * 4. An `m.room.canonical_alias` event if `room_alias_name` is given.
+ *
+ * 5. Events set by the `preset`. Currently these are the `m.room.join_rules`,
  *    `m.room.history_visibility`, and `m.room.guest_access` state events.
  *
- * 5. Events listed in `initial_state`, in the order that they are
+ * 6. Events listed in `initial_state`, in the order that they are
  *    listed.
  *
- * 6. Events implied by `name` and `topic` (`m.room.name` and `m.room.topic`
+ * 7. Events implied by `name` and `topic` (`m.room.name` and `m.room.topic`
  *    state events).
  *
- * 7. Invite events implied by `invite` and `invite_3pid` (`m.room.member` with
+ * 8. Invite events implied by `invite` and `invite_3pid` (`m.room.member` with
  *    `membership: invite` and `m.room.third_party_invite`).
  *
  * The available presets do the following with respect to room state:
@@ -73,17 +75,20 @@ public:
     ///    (and not other members) permission to send state events. Overridden
     ///    by the `power_level_content_override` parameter.
     ///
-    /// 4. Events set by the `preset`. Currently these are the
+    /// 4. An `m.room.canonical_alias` event if `room_alias_name` is given.
+    ///
+    /// 5. Events set by the `preset`. Currently these are the
     /// `m.room.join_rules`,
     ///    `m.room.history_visibility`, and `m.room.guest_access` state events.
     ///
-    /// 5. Events listed in `initial_state`, in the order that they are
+    /// 6. Events listed in `initial_state`, in the order that they are
     ///    listed.
     ///
-    /// 6. Events implied by `name` and `topic` (`m.room.name` and `m.room.topic`
+    /// 7. Events implied by `name` and `topic` (`m.room.name` and
+    /// `m.room.topic`
     ///    state events).
     ///
-    /// 7. Invite events implied by `invite` and `invite_3pid` (`m.room.member`
+    /// 8. Invite events implied by `invite` and `invite_3pid` (`m.room.member`
     /// with
     ///    `membership: invite` and `m.room.third_party_invite`).
     ///
@@ -132,17 +137,20 @@ public:
     ///    (and not other members) permission to send state events. Overridden
     ///    by the `power_level_content_override` parameter.
     ///
-    /// 4. Events set by the `preset`. Currently these are the
+    /// 4. An `m.room.canonical_alias` event if `room_alias_name` is given.
+    ///
+    /// 5. Events set by the `preset`. Currently these are the
     /// `m.room.join_rules`,
     ///    `m.room.history_visibility`, and `m.room.guest_access` state events.
     ///
-    /// 5. Events listed in `initial_state`, in the order that they are
+    /// 6. Events listed in `initial_state`, in the order that they are
     ///    listed.
     ///
-    /// 6. Events implied by `name` and `topic` (`m.room.name` and `m.room.topic`
+    /// 7. Events implied by `name` and `topic` (`m.room.name` and
+    /// `m.room.topic`
     ///    state events).
     ///
-    /// 7. Invite events implied by `invite` and `invite_3pid` (`m.room.member`
+    /// 8. Invite events implied by `invite` and `invite_3pid` (`m.room.member`
     /// with
     ///    `membership: invite` and `m.room.third_party_invite`).
     ///
@@ -190,7 +198,8 @@ public:
      *   would be `#foo:example.com`.
      *
      *   The complete room alias will become the canonical alias for
-     *   the room.
+     *   the room and an `m.room.canonical_alias` event will be sent
+     *   into the room.
      *
      * \param name
      *   If this is included, an `m.room.name` event will be sent
@@ -218,9 +227,10 @@ public:
      *
      * \param creationContent
      *   Extra keys, such as `m.federate`, to be added to the content
-     *   of the [`m.room.create`](client-server-api/#mroomcreate) event. The
-     * server will clobber the following keys: `creator`, `room_version`. Future
-     * versions of the specification may allow the server to clobber other keys.
+     *   of the [`m.room.create`](/client-server-api/#mroomcreate) event. The
+     * server will overwrite the following keys: `creator`, `room_version`.
+     * Future versions of the specification may allow the server to overwrite
+     * other keys.
      *
      * \param initialState
      *   A list of state events to set in the new room. This allows
@@ -229,7 +239,7 @@ public:
      *   with type, state_key and content keys set.
      *
      *   Takes precedence over events set by `preset`, but gets
-     *   overriden by `name` and `topic` keys.
+     *   overridden by `name` and `topic` keys.
      *
      * \param preset
      *   Convenience parameter for setting various default state events
@@ -249,7 +259,7 @@ public:
      * \param powerLevelContentOverride
      *   The power level content to override in the default power level
      *   event. This object is applied on top of the generated
-     *   [`m.room.power_levels`](client-server-api/#mroompower_levels)
+     *   [`m.room.power_levels`](/client-server-api/#mroompower_levels)
      *   event content prior to it being sent to the room. Defaults to
      *   overriding nothing.
      */
diff --git a/lib/csapi/cross_signing.cpp b/lib/csapi/cross_signing.cpp
index 1fa0e949..83136d71 100644
--- a/lib/csapi/cross_signing.cpp
+++ b/lib/csapi/cross_signing.cpp
@@ -9,23 +9,25 @@ using namespace Quotient;
 UploadCrossSigningKeysJob::UploadCrossSigningKeysJob(
     const Omittable<CrossSigningKey>& masterKey,
     const Omittable<CrossSigningKey>& selfSigningKey,
-    const Omittable<CrossSigningKey>& userSigningKey)
+    const Omittable<CrossSigningKey>& userSigningKey,
+    const Omittable<AuthenticationData>& auth)
     : BaseJob(HttpVerb::Post, QStringLiteral("UploadCrossSigningKeysJob"),
-              makePath("/_matrix/client/r0", "/keys/device_signing/upload"))
+              makePath("/_matrix/client/v3", "/keys/device_signing/upload"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("master_key"), masterKey);
-    addParam<IfNotEmpty>(_data, QStringLiteral("self_signing_key"),
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("master_key"), masterKey);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("self_signing_key"),
                          selfSigningKey);
-    addParam<IfNotEmpty>(_data, QStringLiteral("user_signing_key"),
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("user_signing_key"),
                          userSigningKey);
-    setRequestData(std::move(_data));
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    setRequestData({ _dataJson });
 }
 
 UploadCrossSigningSignaturesJob::UploadCrossSigningSignaturesJob(
     const QHash<QString, QHash<QString, QJsonObject>>& signatures)
     : BaseJob(HttpVerb::Post, QStringLiteral("UploadCrossSigningSignaturesJob"),
-              makePath("/_matrix/client/r0", "/keys/signatures/upload"))
+              makePath("/_matrix/client/v3", "/keys/signatures/upload"))
 {
-    setRequestData(RequestData(toJson(signatures)));
+    setRequestData({ toJson(signatures) });
 }
diff --git a/lib/csapi/cross_signing.h b/lib/csapi/cross_signing.h
index 617b61d1..6cea73e6 100644
--- a/lib/csapi/cross_signing.h
+++ b/lib/csapi/cross_signing.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include "csapi/definitions/auth_data.h"
 #include "csapi/definitions/cross_signing_key.h"
 
 #include "jobs/basejob.h"
@@ -35,11 +36,16 @@ public:
      *   the accompanying master key, or by the user\'s most recently
      *   uploaded master key if no master key is included in the
      *   request.
+     *
+     * \param auth
+     *   Additional authentication information for the
+     *   user-interactive authentication API.
      */
     explicit UploadCrossSigningKeysJob(
         const Omittable<CrossSigningKey>& masterKey = none,
         const Omittable<CrossSigningKey>& selfSigningKey = none,
-        const Omittable<CrossSigningKey>& userSigningKey = none);
+        const Omittable<CrossSigningKey>& userSigningKey = none,
+        const Omittable<AuthenticationData>& auth = none);
 };
 
 /*! \brief Upload cross-signing signatures.
@@ -55,7 +61,7 @@ public:
      *   The signatures to be published.
      */
     explicit UploadCrossSigningSignaturesJob(
-        const QHash<QString, QHash<QString, QJsonObject>>& signatures = {});
+        const QHash<QString, QHash<QString, QJsonObject>>& signatures);
 
     // Result properties
 
diff --git a/lib/csapi/definitions/auth_data.h b/lib/csapi/definitions/auth_data.h
index e92596d0..a9972323 100644
--- a/lib/csapi/definitions/auth_data.h
+++ b/lib/csapi/definitions/auth_data.h
@@ -10,7 +10,10 @@ namespace Quotient {
 /// Used by clients to submit authentication information to the
 /// interactive-authentication API
 struct AuthenticationData {
-    /// The login type that the client is attempting to complete.
+    /// The authentication type that the client is attempting to complete.
+    /// May be omitted if `session` is given, and the client is reissuing a
+    /// request which it believes has been completed out-of-band (for example,
+    /// via the [fallback mechanism](#fallback)).
     QString type;
 
     /// The value of the session key given by the homeserver.
@@ -25,7 +28,7 @@ struct JsonObjectConverter<AuthenticationData> {
     static void dumpTo(QJsonObject& jo, const AuthenticationData& pod)
     {
         fillJson(jo, pod.authInfo);
-        addParam<>(jo, QStringLiteral("type"), pod.type);
+        addParam<IfNotEmpty>(jo, QStringLiteral("type"), pod.type);
         addParam<IfNotEmpty>(jo, QStringLiteral("session"), pod.session);
     }
     static void fillFrom(QJsonObject jo, AuthenticationData& pod)
diff --git a/lib/csapi/definitions/openid_token.h b/lib/csapi/definitions/openid_token.h
index 3c447321..9b026dea 100644
--- a/lib/csapi/definitions/openid_token.h
+++ b/lib/csapi/definitions/openid_token.h
@@ -8,7 +8,7 @@
 
 namespace Quotient {
 
-struct OpenidToken {
+struct OpenIdCredentials {
     /// An access token the consumer may use to verify the identity of
     /// the person who generated the token. This is given to the federation
     /// API `GET /openid/userinfo` to verify the user's identity.
@@ -27,8 +27,8 @@ struct OpenidToken {
 };
 
 template <>
-struct JsonObjectConverter<OpenidToken> {
-    static void dumpTo(QJsonObject& jo, const OpenidToken& pod)
+struct JsonObjectConverter<OpenIdCredentials> {
+    static void dumpTo(QJsonObject& jo, const OpenIdCredentials& pod)
     {
         addParam<>(jo, QStringLiteral("access_token"), pod.accessToken);
         addParam<>(jo, QStringLiteral("token_type"), pod.tokenType);
@@ -36,7 +36,7 @@ struct JsonObjectConverter<OpenidToken> {
                    pod.matrixServerName);
         addParam<>(jo, QStringLiteral("expires_in"), pod.expiresIn);
     }
-    static void fillFrom(const QJsonObject& jo, OpenidToken& pod)
+    static void fillFrom(const QJsonObject& jo, OpenIdCredentials& pod)
     {
         fromJson(jo.value("access_token"_ls), pod.accessToken);
         fromJson(jo.value("token_type"_ls), pod.tokenType);
diff --git a/lib/csapi/definitions/public_rooms_response.h b/lib/csapi/definitions/public_rooms_response.h
index 2938b4ec..d0a2595c 100644
--- a/lib/csapi/definitions/public_rooms_response.h
+++ b/lib/csapi/definitions/public_rooms_response.h
@@ -9,9 +9,6 @@
 namespace Quotient {
 
 struct PublicRoomsChunk {
-    /// Aliases of the room. May be empty.
-    QStringList aliases;
-
     /// The canonical alias of the room, if any.
     QString canonicalAlias;
 
@@ -49,7 +46,6 @@ template <>
 struct JsonObjectConverter<PublicRoomsChunk> {
     static void dumpTo(QJsonObject& jo, const PublicRoomsChunk& pod)
     {
-        addParam<IfNotEmpty>(jo, QStringLiteral("aliases"), pod.aliases);
         addParam<IfNotEmpty>(jo, QStringLiteral("canonical_alias"),
                              pod.canonicalAlias);
         addParam<IfNotEmpty>(jo, QStringLiteral("name"), pod.name);
@@ -64,7 +60,6 @@ struct JsonObjectConverter<PublicRoomsChunk> {
     }
     static void fillFrom(const QJsonObject& jo, PublicRoomsChunk& pod)
     {
-        fromJson(jo.value("aliases"_ls), pod.aliases);
         fromJson(jo.value("canonical_alias"_ls), pod.canonicalAlias);
         fromJson(jo.value("name"_ls), pod.name);
         fromJson(jo.value("num_joined_members"_ls), pod.numJoinedMembers);
@@ -77,44 +72,4 @@ struct JsonObjectConverter<PublicRoomsChunk> {
     }
 };
 
-/// A list of the rooms on the server.
-struct PublicRoomsResponse {
-    /// A paginated chunk of public rooms.
-    QVector<PublicRoomsChunk> chunk;
-
-    /// A pagination token for the response. The absence of this token
-    /// means there are no more results to fetch and the client should
-    /// stop paginating.
-    QString nextBatch;
-
-    /// A pagination token that allows fetching previous results. The
-    /// absence of this token means there are no results before this
-    /// batch, i.e. this is the first batch.
-    QString prevBatch;
-
-    /// An estimate on the total number of public rooms, if the
-    /// server has an estimate.
-    Omittable<int> totalRoomCountEstimate;
-};
-
-template <>
-struct JsonObjectConverter<PublicRoomsResponse> {
-    static void dumpTo(QJsonObject& jo, const PublicRoomsResponse& pod)
-    {
-        addParam<>(jo, QStringLiteral("chunk"), pod.chunk);
-        addParam<IfNotEmpty>(jo, QStringLiteral("next_batch"), pod.nextBatch);
-        addParam<IfNotEmpty>(jo, QStringLiteral("prev_batch"), pod.prevBatch);
-        addParam<IfNotEmpty>(jo, QStringLiteral("total_room_count_estimate"),
-                             pod.totalRoomCountEstimate);
-    }
-    static void fillFrom(const QJsonObject& jo, PublicRoomsResponse& pod)
-    {
-        fromJson(jo.value("chunk"_ls), pod.chunk);
-        fromJson(jo.value("next_batch"_ls), pod.nextBatch);
-        fromJson(jo.value("prev_batch"_ls), pod.prevBatch);
-        fromJson(jo.value("total_room_count_estimate"_ls),
-                 pod.totalRoomCountEstimate);
-    }
-};
-
 } // namespace Quotient
diff --git a/lib/csapi/definitions/push_condition.h b/lib/csapi/definitions/push_condition.h
index ce66d075..6a048ba8 100644
--- a/lib/csapi/definitions/push_condition.h
+++ b/lib/csapi/definitions/push_condition.h
@@ -24,9 +24,7 @@ struct PushCondition {
     QString key;
 
     /// Required for `event_match` conditions. The glob-style pattern to
-    /// match against. Patterns with no special glob characters should be
-    /// treated as having asterisks prepended and appended when testing the
-    /// condition.
+    /// match against.
     QString pattern;
 
     /// Required for `room_member_count` conditions. A decimal integer
diff --git a/lib/csapi/device_management.cpp b/lib/csapi/device_management.cpp
index da6dbc76..6f2badee 100644
--- a/lib/csapi/device_management.cpp
+++ b/lib/csapi/device_management.cpp
@@ -9,53 +9,53 @@ using namespace Quotient;
 QUrl GetDevicesJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/devices"));
+                                   makePath("/_matrix/client/v3", "/devices"));
 }
 
 GetDevicesJob::GetDevicesJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetDevicesJob"),
-              makePath("/_matrix/client/r0", "/devices"))
+              makePath("/_matrix/client/v3", "/devices"))
 {}
 
 QUrl GetDeviceJob::makeRequestUrl(QUrl baseUrl, const QString& deviceId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/devices/",
+                                   makePath("/_matrix/client/v3", "/devices/",
                                             deviceId));
 }
 
 GetDeviceJob::GetDeviceJob(const QString& deviceId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetDeviceJob"),
-              makePath("/_matrix/client/r0", "/devices/", deviceId))
+              makePath("/_matrix/client/v3", "/devices/", deviceId))
 {}
 
 UpdateDeviceJob::UpdateDeviceJob(const QString& deviceId,
                                  const QString& displayName)
     : BaseJob(HttpVerb::Put, QStringLiteral("UpdateDeviceJob"),
-              makePath("/_matrix/client/r0", "/devices/", deviceId))
+              makePath("/_matrix/client/v3", "/devices/", deviceId))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("display_name"), displayName);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("display_name"), displayName);
+    setRequestData({ _dataJson });
 }
 
 DeleteDeviceJob::DeleteDeviceJob(const QString& deviceId,
                                  const Omittable<AuthenticationData>& auth)
     : BaseJob(HttpVerb::Delete, QStringLiteral("DeleteDeviceJob"),
-              makePath("/_matrix/client/r0", "/devices/", deviceId))
+              makePath("/_matrix/client/v3", "/devices/", deviceId))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("auth"), auth);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    setRequestData({ _dataJson });
 }
 
 DeleteDevicesJob::DeleteDevicesJob(const QStringList& devices,
                                    const Omittable<AuthenticationData>& auth)
     : BaseJob(HttpVerb::Post, QStringLiteral("DeleteDevicesJob"),
-              makePath("/_matrix/client/r0", "/delete_devices"))
+              makePath("/_matrix/client/v3", "/delete_devices"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("devices"), devices);
-    addParam<IfNotEmpty>(_data, QStringLiteral("auth"), auth);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("devices"), devices);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/device_management.h b/lib/csapi/device_management.h
index 430d2132..c10389b3 100644
--- a/lib/csapi/device_management.h
+++ b/lib/csapi/device_management.h
@@ -86,7 +86,8 @@ public:
  * This API endpoint uses the [User-Interactive Authentication
  * API](/client-server-api/#user-interactive-authentication-api).
  *
- * Deletes the given device, and invalidates any access token associated with it.
+ * Deletes the given device, and invalidates any access token associated with
+ * it.
  */
 class QUOTIENT_API DeleteDeviceJob : public BaseJob {
 public:
diff --git a/lib/csapi/directory.cpp b/lib/csapi/directory.cpp
index b351b4ef..c1255bb1 100644
--- a/lib/csapi/directory.cpp
+++ b/lib/csapi/directory.cpp
@@ -8,48 +8,48 @@ using namespace Quotient;
 
 SetRoomAliasJob::SetRoomAliasJob(const QString& roomAlias, const QString& roomId)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetRoomAliasJob"),
-              makePath("/_matrix/client/r0", "/directory/room/", roomAlias))
+              makePath("/_matrix/client/v3", "/directory/room/", roomAlias))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("room_id"), roomId);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("room_id"), roomId);
+    setRequestData({ _dataJson });
 }
 
 QUrl GetRoomIdByAliasJob::makeRequestUrl(QUrl baseUrl, const QString& roomAlias)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/directory/room/", roomAlias));
 }
 
 GetRoomIdByAliasJob::GetRoomIdByAliasJob(const QString& roomAlias)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetRoomIdByAliasJob"),
-              makePath("/_matrix/client/r0", "/directory/room/", roomAlias),
+              makePath("/_matrix/client/v3", "/directory/room/", roomAlias),
               false)
 {}
 
 QUrl DeleteRoomAliasJob::makeRequestUrl(QUrl baseUrl, const QString& roomAlias)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/directory/room/", roomAlias));
 }
 
 DeleteRoomAliasJob::DeleteRoomAliasJob(const QString& roomAlias)
     : BaseJob(HttpVerb::Delete, QStringLiteral("DeleteRoomAliasJob"),
-              makePath("/_matrix/client/r0", "/directory/room/", roomAlias))
+              makePath("/_matrix/client/v3", "/directory/room/", roomAlias))
 {}
 
 QUrl GetLocalAliasesJob::makeRequestUrl(QUrl baseUrl, const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/aliases"));
 }
 
 GetLocalAliasesJob::GetLocalAliasesJob(const QString& roomId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetLocalAliasesJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/aliases"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/aliases"))
 {
     addExpectedKey("aliases");
 }
diff --git a/lib/csapi/event_context.cpp b/lib/csapi/event_context.cpp
index 877838e2..4ebbbf98 100644
--- a/lib/csapi/event_context.cpp
+++ b/lib/csapi/event_context.cpp
@@ -20,7 +20,7 @@ QUrl GetEventContextJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
                                         const QString& filter)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/context/", eventId),
                                    queryToGetEventContext(limit, filter));
 }
@@ -30,7 +30,7 @@ GetEventContextJob::GetEventContextJob(const QString& roomId,
                                        Omittable<int> limit,
                                        const QString& filter)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetEventContextJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/context/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/context/",
                        eventId),
               queryToGetEventContext(limit, filter))
 {}
diff --git a/lib/csapi/filter.cpp b/lib/csapi/filter.cpp
index 38c68be7..2469fbd1 100644
--- a/lib/csapi/filter.cpp
+++ b/lib/csapi/filter.cpp
@@ -8,9 +8,9 @@ using namespace Quotient;
 
 DefineFilterJob::DefineFilterJob(const QString& userId, const Filter& filter)
     : BaseJob(HttpVerb::Post, QStringLiteral("DefineFilterJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/filter"))
+              makePath("/_matrix/client/v3", "/user/", userId, "/filter"))
 {
-    setRequestData(RequestData(toJson(filter)));
+    setRequestData({ toJson(filter) });
     addExpectedKey("filter_id");
 }
 
@@ -18,12 +18,12 @@ QUrl GetFilterJob::makeRequestUrl(QUrl baseUrl, const QString& userId,
                                   const QString& filterId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/user/",
+                                   makePath("/_matrix/client/v3", "/user/",
                                             userId, "/filter/", filterId));
 }
 
 GetFilterJob::GetFilterJob(const QString& userId, const QString& filterId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetFilterJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/filter/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/filter/",
                        filterId))
 {}
diff --git a/lib/csapi/inviting.cpp b/lib/csapi/inviting.cpp
index 39d24611..41a8b5be 100644
--- a/lib/csapi/inviting.cpp
+++ b/lib/csapi/inviting.cpp
@@ -9,10 +9,10 @@ using namespace Quotient;
 InviteUserJob::InviteUserJob(const QString& roomId, const QString& userId,
                              const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("InviteUserJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/invite"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/invite"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("user_id"), userId);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("user_id"), userId);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/inviting.h b/lib/csapi/inviting.h
index 21e6cb74..cb9d052b 100644
--- a/lib/csapi/inviting.h
+++ b/lib/csapi/inviting.h
@@ -14,7 +14,7 @@ namespace Quotient {
  * This version of the API requires that the inviter knows the Matrix
  * identifier of the invitee. The other is documented in the*
  * [third party invites
- * section](/client-server-api/#post_matrixclientr0roomsroomidinvite-1).
+ * section](/client-server-api/#post_matrixclientv3roomsroomidinvite-1).
  *
  * This API invites a user to participate in a particular room.
  * They do not start participating in the room until they actually join the
diff --git a/lib/csapi/joining.cpp b/lib/csapi/joining.cpp
index 373c1c6a..cdba95e9 100644
--- a/lib/csapi/joining.cpp
+++ b/lib/csapi/joining.cpp
@@ -10,13 +10,13 @@ JoinRoomByIdJob::JoinRoomByIdJob(
     const QString& roomId, const Omittable<ThirdPartySigned>& thirdPartySigned,
     const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("JoinRoomByIdJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/join"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/join"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("third_party_signed"),
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("third_party_signed"),
                          thirdPartySigned);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
     addExpectedKey("room_id");
 }
 
@@ -32,13 +32,13 @@ JoinRoomJob::JoinRoomJob(const QString& roomIdOrAlias,
                          const Omittable<ThirdPartySigned>& thirdPartySigned,
                          const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("JoinRoomJob"),
-              makePath("/_matrix/client/r0", "/join/", roomIdOrAlias),
+              makePath("/_matrix/client/v3", "/join/", roomIdOrAlias),
               queryToJoinRoom(serverName))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("third_party_signed"),
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("third_party_signed"),
                          thirdPartySigned);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
     addExpectedKey("room_id");
 }
diff --git a/lib/csapi/joining.h b/lib/csapi/joining.h
index f64152f7..233537bb 100644
--- a/lib/csapi/joining.h
+++ b/lib/csapi/joining.h
@@ -22,8 +22,8 @@ namespace Quotient {
  *
  * After a user has joined a room, the room will appear as an entry in the
  * response of the
- * [`/initialSync`](/client-server-api/#get_matrixclientr0initialsync) and
- * [`/sync`](/client-server-api/#get_matrixclientr0sync) APIs.
+ * [`/initialSync`](/client-server-api/#get_matrixclientv3initialsync) and
+ * [`/sync`](/client-server-api/#get_matrixclientv3sync) APIs.
  */
 class QUOTIENT_API JoinRoomByIdJob : public BaseJob {
 public:
@@ -64,8 +64,8 @@ public:
  *
  * After a user has joined a room, the room will appear as an entry in the
  * response of the
- * [`/initialSync`](/client-server-api/#get_matrixclientr0initialsync) and
- * [`/sync`](/client-server-api/#get_matrixclientr0sync) APIs.
+ * [`/initialSync`](/client-server-api/#get_matrixclientv3initialsync) and
+ * [`/sync`](/client-server-api/#get_matrixclientv3sync) APIs.
  */
 class QUOTIENT_API JoinRoomJob : public BaseJob {
 public:
diff --git a/lib/csapi/keys.cpp b/lib/csapi/keys.cpp
index d6bd2fab..2e4978f2 100644
--- a/lib/csapi/keys.cpp
+++ b/lib/csapi/keys.cpp
@@ -7,39 +7,43 @@
 using namespace Quotient;
 
 UploadKeysJob::UploadKeysJob(const Omittable<DeviceKeys>& deviceKeys,
-                             const QHash<QString, QVariant>& oneTimeKeys)
+                             const OneTimeKeys& oneTimeKeys,
+                             const OneTimeKeys& fallbackKeys)
     : BaseJob(HttpVerb::Post, QStringLiteral("UploadKeysJob"),
-              makePath("/_matrix/client/r0", "/keys/upload"))
+              makePath("/_matrix/client/v3", "/keys/upload"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("device_keys"), deviceKeys);
-    addParam<IfNotEmpty>(_data, QStringLiteral("one_time_keys"), oneTimeKeys);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("device_keys"), deviceKeys);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("one_time_keys"),
+                         oneTimeKeys);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("fallback_keys"),
+                         fallbackKeys);
+    setRequestData({ _dataJson });
     addExpectedKey("one_time_key_counts");
 }
 
 QueryKeysJob::QueryKeysJob(const QHash<QString, QStringList>& deviceKeys,
                            Omittable<int> timeout, const QString& token)
     : BaseJob(HttpVerb::Post, QStringLiteral("QueryKeysJob"),
-              makePath("/_matrix/client/r0", "/keys/query"))
+              makePath("/_matrix/client/v3", "/keys/query"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("timeout"), timeout);
-    addParam<>(_data, QStringLiteral("device_keys"), deviceKeys);
-    addParam<IfNotEmpty>(_data, QStringLiteral("token"), token);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("timeout"), timeout);
+    addParam<>(_dataJson, QStringLiteral("device_keys"), deviceKeys);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("token"), token);
+    setRequestData({ _dataJson });
 }
 
 ClaimKeysJob::ClaimKeysJob(
     const QHash<QString, QHash<QString, QString>>& oneTimeKeys,
     Omittable<int> timeout)
     : BaseJob(HttpVerb::Post, QStringLiteral("ClaimKeysJob"),
-              makePath("/_matrix/client/r0", "/keys/claim"))
+              makePath("/_matrix/client/v3", "/keys/claim"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("timeout"), timeout);
-    addParam<>(_data, QStringLiteral("one_time_keys"), oneTimeKeys);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("timeout"), timeout);
+    addParam<>(_dataJson, QStringLiteral("one_time_keys"), oneTimeKeys);
+    setRequestData({ _dataJson });
     addExpectedKey("one_time_keys");
 }
 
@@ -55,13 +59,13 @@ QUrl GetKeysChangesJob::makeRequestUrl(QUrl baseUrl, const QString& from,
                                        const QString& to)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/keys/changes"),
                                    queryToGetKeysChanges(from, to));
 }
 
 GetKeysChangesJob::GetKeysChangesJob(const QString& from, const QString& to)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetKeysChangesJob"),
-              makePath("/_matrix/client/r0", "/keys/changes"),
+              makePath("/_matrix/client/v3", "/keys/changes"),
               queryToGetKeysChanges(from, to))
 {}
diff --git a/lib/csapi/keys.h b/lib/csapi/keys.h
index ce1ca9ed..2f2ebc6d 100644
--- a/lib/csapi/keys.h
+++ b/lib/csapi/keys.h
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include "e2ee/e2ee.h"
+
 #include "csapi/definitions/cross_signing_key.h"
 #include "csapi/definitions/device_keys.h"
 
@@ -30,14 +32,32 @@ public:
      *   by the [key algorithm](/client-server-api/#key-algorithms).
      *
      *   May be absent if no new one-time keys are required.
+     *
+     * \param fallbackKeys
+     *   The public key which should be used if the device's one-time keys
+     *   are exhausted. The fallback key is not deleted once used, but should
+     *   be replaced when additional one-time keys are being uploaded. The
+     *   server will notify the client of the fallback key being used through
+     *   `/sync`.
+     *
+     *   There can only be at most one key per algorithm uploaded, and the
+     * server will only persist one key per algorithm.
+     *
+     *   When uploading a signed key, an additional `fallback: true` key should
+     *   be included to denote that the key is a fallback key.
+     *
+     *   May be absent if a new fallback key is not required.
      */
     explicit UploadKeysJob(const Omittable<DeviceKeys>& deviceKeys = none,
-                           const QHash<QString, QVariant>& oneTimeKeys = {});
+                           const OneTimeKeys& oneTimeKeys = {},
+                           const OneTimeKeys& fallbackKeys = {});
 
     // Result properties
 
     /// For each key algorithm, the number of unclaimed one-time keys
     /// of that type currently held on the server for this device.
+    /// If an algorithm is not listed, the count for that algorithm
+    /// is to be assumed zero.
     QHash<QString, int> oneTimeKeyCounts() const
     {
         return loadFromJson<QHash<QString, int>>("one_time_key_counts"_ls);
@@ -207,9 +227,12 @@ public:
     ///
     /// See the [key algorithms](/client-server-api/#key-algorithms) section for
     /// information on the Key Object format.
-    QHash<QString, QHash<QString, QVariant>> oneTimeKeys() const
+    ///
+    /// If necessary, the claimed key might be a fallback key. Fallback
+    /// keys are re-used by the server until replaced by the device.
+    QHash<QString, QHash<QString, OneTimeKeys>> oneTimeKeys() const
     {
-        return loadFromJson<QHash<QString, QHash<QString, QVariant>>>(
+        return loadFromJson<QHash<QString, QHash<QString, OneTimeKeys>>>(
             "one_time_keys"_ls);
     }
 };
@@ -233,7 +256,7 @@ public:
      * \param from
      *   The desired start point of the list. Should be the `next_batch` field
      *   from a response to an earlier call to
-     * [`/sync`](/client-server-api/#get_matrixclientr0sync). Users who have not
+     * [`/sync`](/client-server-api/#get_matrixclientv3sync). Users who have not
      *   uploaded new device identity keys since this point, nor deleted
      *   existing devices with identity keys since then, will be excluded
      *   from the results.
@@ -241,7 +264,7 @@ public:
      * \param to
      *   The desired end point of the list. Should be the `next_batch`
      *   field from a recent call to
-     * [`/sync`](/client-server-api/#get_matrixclientr0sync) - typically the
+     * [`/sync`](/client-server-api/#get_matrixclientv3sync) - typically the
      * most recent such call. This may be used by the server as a hint to check
      * its caches are up to date.
      */
diff --git a/lib/csapi/kicking.cpp b/lib/csapi/kicking.cpp
index 433e592c..4ca39c4c 100644
--- a/lib/csapi/kicking.cpp
+++ b/lib/csapi/kicking.cpp
@@ -9,10 +9,10 @@ using namespace Quotient;
 KickJob::KickJob(const QString& roomId, const QString& userId,
                  const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("KickJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/kick"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/kick"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("user_id"), userId);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("user_id"), userId);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/knocking.cpp b/lib/csapi/knocking.cpp
index 73e13e6e..b9da4b9b 100644
--- a/lib/csapi/knocking.cpp
+++ b/lib/csapi/knocking.cpp
@@ -16,11 +16,11 @@ auto queryToKnockRoom(const QStringList& serverName)
 KnockRoomJob::KnockRoomJob(const QString& roomIdOrAlias,
                            const QStringList& serverName, const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("KnockRoomJob"),
-              makePath("/_matrix/client/r0", "/knock/", roomIdOrAlias),
+              makePath("/_matrix/client/v3", "/knock/", roomIdOrAlias),
               queryToKnockRoom(serverName))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
     addExpectedKey("room_id");
 }
diff --git a/lib/csapi/knocking.h b/lib/csapi/knocking.h
index e3645b59..f43033a8 100644
--- a/lib/csapi/knocking.h
+++ b/lib/csapi/knocking.h
@@ -25,7 +25,7 @@ namespace Quotient {
  * history visibility to the user.
  *
  * The knock will appear as an entry in the response of the
- * [`/sync`](/client-server-api/#get_matrixclientr0sync) API.
+ * [`/sync`](/client-server-api/#get_matrixclientv3sync) API.
  */
 class QUOTIENT_API KnockRoomJob : public BaseJob {
 public:
diff --git a/lib/csapi/leaving.cpp b/lib/csapi/leaving.cpp
index 0e5386be..ba91f26a 100644
--- a/lib/csapi/leaving.cpp
+++ b/lib/csapi/leaving.cpp
@@ -8,21 +8,21 @@ using namespace Quotient;
 
 LeaveRoomJob::LeaveRoomJob(const QString& roomId, const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("LeaveRoomJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/leave"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/leave"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
 
 QUrl ForgetRoomJob::makeRequestUrl(QUrl baseUrl, const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/forget"));
 }
 
 ForgetRoomJob::ForgetRoomJob(const QString& roomId)
     : BaseJob(HttpVerb::Post, QStringLiteral("ForgetRoomJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/forget"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/forget"))
 {}
diff --git a/lib/csapi/list_joined_rooms.cpp b/lib/csapi/list_joined_rooms.cpp
index 22ba04da..cdcf3eb2 100644
--- a/lib/csapi/list_joined_rooms.cpp
+++ b/lib/csapi/list_joined_rooms.cpp
@@ -9,12 +9,12 @@ using namespace Quotient;
 QUrl GetJoinedRoomsJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/joined_rooms"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/joined_rooms"));
 }
 
 GetJoinedRoomsJob::GetJoinedRoomsJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetJoinedRoomsJob"),
-              makePath("/_matrix/client/r0", "/joined_rooms"))
+              makePath("/_matrix/client/v3", "/joined_rooms"))
 {
     addExpectedKey("joined_rooms");
 }
diff --git a/lib/csapi/list_public_rooms.cpp b/lib/csapi/list_public_rooms.cpp
index 25f8da5c..4deecfc2 100644
--- a/lib/csapi/list_public_rooms.cpp
+++ b/lib/csapi/list_public_rooms.cpp
@@ -10,25 +10,25 @@ QUrl GetRoomVisibilityOnDirectoryJob::makeRequestUrl(QUrl baseUrl,
                                                      const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/directory/list/room/", roomId));
 }
 
 GetRoomVisibilityOnDirectoryJob::GetRoomVisibilityOnDirectoryJob(
     const QString& roomId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetRoomVisibilityOnDirectoryJob"),
-              makePath("/_matrix/client/r0", "/directory/list/room/", roomId),
+              makePath("/_matrix/client/v3", "/directory/list/room/", roomId),
               false)
 {}
 
 SetRoomVisibilityOnDirectoryJob::SetRoomVisibilityOnDirectoryJob(
     const QString& roomId, const QString& visibility)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetRoomVisibilityOnDirectoryJob"),
-              makePath("/_matrix/client/r0", "/directory/list/room/", roomId))
+              makePath("/_matrix/client/v3", "/directory/list/room/", roomId))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("visibility"), visibility);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("visibility"), visibility);
+    setRequestData({ _dataJson });
 }
 
 auto queryToGetPublicRooms(Omittable<int> limit, const QString& since,
@@ -46,7 +46,7 @@ QUrl GetPublicRoomsJob::makeRequestUrl(QUrl baseUrl, Omittable<int> limit,
                                        const QString& server)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/publicRooms"),
                                    queryToGetPublicRooms(limit, since, server));
 }
@@ -54,7 +54,7 @@ QUrl GetPublicRoomsJob::makeRequestUrl(QUrl baseUrl, Omittable<int> limit,
 GetPublicRoomsJob::GetPublicRoomsJob(Omittable<int> limit, const QString& since,
                                      const QString& server)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetPublicRoomsJob"),
-              makePath("/_matrix/client/r0", "/publicRooms"),
+              makePath("/_matrix/client/v3", "/publicRooms"),
               queryToGetPublicRooms(limit, since, server), {}, false)
 {
     addExpectedKey("chunk");
@@ -74,17 +74,17 @@ QueryPublicRoomsJob::QueryPublicRoomsJob(const QString& server,
                                          Omittable<bool> includeAllNetworks,
                                          const QString& thirdPartyInstanceId)
     : BaseJob(HttpVerb::Post, QStringLiteral("QueryPublicRoomsJob"),
-              makePath("/_matrix/client/r0", "/publicRooms"),
+              makePath("/_matrix/client/v3", "/publicRooms"),
               queryToQueryPublicRooms(server))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("limit"), limit);
-    addParam<IfNotEmpty>(_data, QStringLiteral("since"), since);
-    addParam<IfNotEmpty>(_data, QStringLiteral("filter"), filter);
-    addParam<IfNotEmpty>(_data, QStringLiteral("include_all_networks"),
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("limit"), limit);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("since"), since);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("filter"), filter);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("include_all_networks"),
                          includeAllNetworks);
-    addParam<IfNotEmpty>(_data, QStringLiteral("third_party_instance_id"),
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("third_party_instance_id"),
                          thirdPartyInstanceId);
-    setRequestData(std::move(_data));
+    setRequestData({ _dataJson });
     addExpectedKey("chunk");
 }
diff --git a/lib/csapi/login.cpp b/lib/csapi/login.cpp
index 71fd93c5..81e603b5 100644
--- a/lib/csapi/login.cpp
+++ b/lib/csapi/login.cpp
@@ -9,29 +9,33 @@ using namespace Quotient;
 QUrl GetLoginFlowsJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/login"));
+                                   makePath("/_matrix/client/v3", "/login"));
 }
 
 GetLoginFlowsJob::GetLoginFlowsJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetLoginFlowsJob"),
-              makePath("/_matrix/client/r0", "/login"), false)
+              makePath("/_matrix/client/v3", "/login"), false)
 {}
 
 LoginJob::LoginJob(const QString& type,
                    const Omittable<UserIdentifier>& identifier,
                    const QString& password, const QString& token,
                    const QString& deviceId,
-                   const QString& initialDeviceDisplayName)
+                   const QString& initialDeviceDisplayName,
+                   Omittable<bool> refreshToken)
     : BaseJob(HttpVerb::Post, QStringLiteral("LoginJob"),
-              makePath("/_matrix/client/r0", "/login"), false)
+              makePath("/_matrix/client/v3", "/login"), false)
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("type"), type);
-    addParam<IfNotEmpty>(_data, QStringLiteral("identifier"), identifier);
-    addParam<IfNotEmpty>(_data, QStringLiteral("password"), password);
-    addParam<IfNotEmpty>(_data, QStringLiteral("token"), token);
-    addParam<IfNotEmpty>(_data, QStringLiteral("device_id"), deviceId);
-    addParam<IfNotEmpty>(_data, QStringLiteral("initial_device_display_name"),
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("type"), type);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("identifier"), identifier);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("password"), password);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("token"), token);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("device_id"), deviceId);
+    addParam<IfNotEmpty>(_dataJson,
+                         QStringLiteral("initial_device_display_name"),
                          initialDeviceDisplayName);
-    setRequestData(std::move(_data));
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("refresh_token"),
+                         refreshToken);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/login.h b/lib/csapi/login.h
index ce6951eb..b9f14266 100644
--- a/lib/csapi/login.h
+++ b/lib/csapi/login.h
@@ -111,12 +111,16 @@ public:
      * \param initialDeviceDisplayName
      *   A display name to assign to the newly-created device. Ignored
      *   if `device_id` corresponds to a known device.
+     *
+     * \param refreshToken
+     *   If true, the client supports refresh tokens.
      */
     explicit LoginJob(const QString& type,
                       const Omittable<UserIdentifier>& identifier = none,
                       const QString& password = {}, const QString& token = {},
                       const QString& deviceId = {},
-                      const QString& initialDeviceDisplayName = {});
+                      const QString& initialDeviceDisplayName = {},
+                      Omittable<bool> refreshToken = none);
 
     // Result properties
 
@@ -130,15 +134,23 @@ public:
         return loadFromJson<QString>("access_token"_ls);
     }
 
-    /// The server_name of the homeserver on which the account has
-    /// been registered.
-    ///
-    /// **Deprecated**. Clients should extract the server_name from
-    /// `user_id` (by splitting at the first colon) if they require
-    /// it. Note also that `homeserver` is not spelt this way.
-    QString homeServer() const
+    /// A refresh token for the account. This token can be used to
+    /// obtain a new access token when it expires by calling the
+    /// `/refresh` endpoint.
+    QString refreshToken() const
+    {
+        return loadFromJson<QString>("refresh_token"_ls);
+    }
+
+    /// The lifetime of the access token, in milliseconds. Once
+    /// the access token has expired a new access token can be
+    /// obtained by using the provided refresh token. If no
+    /// refresh token is provided, the client will need to re-log in
+    /// to obtain a new access token. If not given, the client can
+    /// assume that the access token will not expire.
+    Omittable<int> expiresInMs() const
     {
-        return loadFromJson<QString>("home_server"_ls);
+        return loadFromJson<Omittable<int>>("expires_in_ms"_ls);
     }
 
     /// ID of the logged-in device. Will be the same as the
diff --git a/lib/csapi/logout.cpp b/lib/csapi/logout.cpp
index e8083e31..9ec54c71 100644
--- a/lib/csapi/logout.cpp
+++ b/lib/csapi/logout.cpp
@@ -9,21 +9,21 @@ using namespace Quotient;
 QUrl LogoutJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/logout"));
+                                   makePath("/_matrix/client/v3", "/logout"));
 }
 
 LogoutJob::LogoutJob()
     : BaseJob(HttpVerb::Post, QStringLiteral("LogoutJob"),
-              makePath("/_matrix/client/r0", "/logout"))
+              makePath("/_matrix/client/v3", "/logout"))
 {}
 
 QUrl LogoutAllJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/logout/all"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/logout/all"));
 }
 
 LogoutAllJob::LogoutAllJob()
     : BaseJob(HttpVerb::Post, QStringLiteral("LogoutAllJob"),
-              makePath("/_matrix/client/r0", "/logout/all"))
+              makePath("/_matrix/client/v3", "/logout/all"))
 {}
diff --git a/lib/csapi/message_pagination.cpp b/lib/csapi/message_pagination.cpp
index 1a93b75b..0b2c99ce 100644
--- a/lib/csapi/message_pagination.cpp
+++ b/lib/csapi/message_pagination.cpp
@@ -11,7 +11,7 @@ auto queryToGetRoomEvents(const QString& from, const QString& to,
                           const QString& filter)
 {
     QUrlQuery _q;
-    addParam<>(_q, QStringLiteral("from"), from);
+    addParam<IfNotEmpty>(_q, QStringLiteral("from"), from);
     addParam<IfNotEmpty>(_q, QStringLiteral("to"), to);
     addParam<>(_q, QStringLiteral("dir"), dir);
     addParam<IfNotEmpty>(_q, QStringLiteral("limit"), limit);
@@ -20,20 +20,23 @@ auto queryToGetRoomEvents(const QString& from, const QString& to,
 }
 
 QUrl GetRoomEventsJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
-                                      const QString& from, const QString& dir,
+                                      const QString& dir, const QString& from,
                                       const QString& to, Omittable<int> limit,
                                       const QString& filter)
 {
     return BaseJob::makeRequestUrl(
         std::move(baseUrl),
-        makePath("/_matrix/client/r0", "/rooms/", roomId, "/messages"),
+        makePath("/_matrix/client/v3", "/rooms/", roomId, "/messages"),
         queryToGetRoomEvents(from, to, dir, limit, filter));
 }
 
-GetRoomEventsJob::GetRoomEventsJob(const QString& roomId, const QString& from,
-                                   const QString& dir, const QString& to,
+GetRoomEventsJob::GetRoomEventsJob(const QString& roomId, const QString& dir,
+                                   const QString& from, const QString& to,
                                    Omittable<int> limit, const QString& filter)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetRoomEventsJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/messages"),
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/messages"),
               queryToGetRoomEvents(from, to, dir, limit, filter))
-{}
+{
+    addExpectedKey("start");
+    addExpectedKey("chunk");
+}
diff --git a/lib/csapi/message_pagination.h b/lib/csapi/message_pagination.h
index 8c18f104..9831ae2d 100644
--- a/lib/csapi/message_pagination.h
+++ b/lib/csapi/message_pagination.h
@@ -25,20 +25,30 @@ public:
      * \param roomId
      *   The room to get events from.
      *
+     * \param dir
+     *   The direction to return events from. If this is set to `f`, events
+     *   will be returned in chronological order starting at `from`. If it
+     *   is set to `b`, events will be returned in *reverse* chronological
+     *   order, again starting at `from`.
+     *
      * \param from
      *   The token to start returning events from. This token can be obtained
-     *   from a `prev_batch` token returned for each room by the sync API,
-     *   or from a `start` or `end` token returned by a previous request
-     *   to this endpoint.
+     *   from a `prev_batch` or `next_batch` token returned by the `/sync`
+     * endpoint, or from an `end` token returned by a previous request to this
+     * endpoint.
      *
-     * \param dir
-     *   The direction to return events from.
+     *   This endpoint can also accept a value returned as a `start` token
+     *   by a previous request to this endpoint, though servers are not
+     *   required to support this. Clients should not rely on the behaviour.
+     *
+     *   If it is not provided, the homeserver shall return a list of messages
+     *   from the first or last (per the value of the `dir` parameter) visible
+     *   event in the room history for the requesting user.
      *
      * \param to
      *   The token to stop returning events at. This token can be obtained from
-     *   a `prev_batch` token returned for each room by the sync endpoint,
-     *   or from a `start` or `end` token returned by a previous request to
-     *   this endpoint.
+     *   a `prev_batch` or `next_batch` token returned by the `/sync` endpoint,
+     *   or from an `end` token returned by a previous request to this endpoint.
      *
      * \param limit
      *   The maximum number of events to return. Default: 10.
@@ -46,8 +56,8 @@ public:
      * \param filter
      *   A JSON RoomEventFilter to filter returned events with.
      */
-    explicit GetRoomEventsJob(const QString& roomId, const QString& from,
-                              const QString& dir, const QString& to = {},
+    explicit GetRoomEventsJob(const QString& roomId, const QString& dir,
+                              const QString& from = {}, const QString& to = {},
                               Omittable<int> limit = none,
                               const QString& filter = {});
 
@@ -57,25 +67,34 @@ public:
      * is necessary but the job itself isn't.
      */
     static QUrl makeRequestUrl(QUrl baseUrl, const QString& roomId,
-                               const QString& from, const QString& dir,
+                               const QString& dir, const QString& from = {},
                                const QString& to = {},
                                Omittable<int> limit = none,
                                const QString& filter = {});
 
     // Result properties
 
-    /// The token the pagination starts from. If `dir=b` this will be
-    /// the token supplied in `from`.
+    /// A token corresponding to the start of `chunk`. This will be the same as
+    /// the value given in `from`.
     QString begin() const { return loadFromJson<QString>("start"_ls); }
 
-    /// The token the pagination ends at. If `dir=b` this token should
-    /// be used again to request even earlier events.
+    /// A token corresponding to the end of `chunk`. This token can be passed
+    /// back to this endpoint to request further events.
+    ///
+    /// If no further events are available (either because we have
+    /// reached the start of the timeline, or because the user does
+    /// not have permission to see any more events), this property
+    /// is omitted from the response.
     QString end() const { return loadFromJson<QString>("end"_ls); }
 
     /// A list of room events. The order depends on the `dir` parameter.
     /// For `dir=b` events will be in reverse-chronological order,
-    /// for `dir=f` in chronological order, so that events start
-    /// at the `from` point.
+    /// for `dir=f` in chronological order. (The exact definition of
+    /// `chronological` is dependent on the server implementation.)
+    ///
+    /// Note that an empty `chunk` does not *necessarily* imply that no more
+    /// events are available. Clients should continue to paginate until no `end`
+    /// property is returned.
     RoomEvents chunk() { return takeFromJson<RoomEvents>("chunk"_ls); }
 
     /// A list of state events relevant to showing the `chunk`. For example, if
@@ -86,7 +105,7 @@ public:
     /// may remove membership events which would have already been
     /// sent to the client in prior calls to this endpoint, assuming
     /// the membership of those members has not changed.
-    StateEvents state() { return takeFromJson<StateEvents>("state"_ls); }
+    RoomEvents state() { return takeFromJson<RoomEvents>("state"_ls); }
 };
 
 } // namespace Quotient
diff --git a/lib/csapi/notifications.cpp b/lib/csapi/notifications.cpp
index 1e523c6f..38aed174 100644
--- a/lib/csapi/notifications.cpp
+++ b/lib/csapi/notifications.cpp
@@ -21,7 +21,7 @@ QUrl GetNotificationsJob::makeRequestUrl(QUrl baseUrl, const QString& from,
                                          const QString& only)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/notifications"),
                                    queryToGetNotifications(from, limit, only));
 }
@@ -30,7 +30,7 @@ GetNotificationsJob::GetNotificationsJob(const QString& from,
                                          Omittable<int> limit,
                                          const QString& only)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetNotificationsJob"),
-              makePath("/_matrix/client/r0", "/notifications"),
+              makePath("/_matrix/client/v3", "/notifications"),
               queryToGetNotifications(from, limit, only))
 {
     addExpectedKey("notifications");
diff --git a/lib/csapi/notifications.h b/lib/csapi/notifications.h
index 23211758..48167877 100644
--- a/lib/csapi/notifications.h
+++ b/lib/csapi/notifications.h
@@ -43,7 +43,8 @@ public:
     /*! \brief Gets a list of events that the user has been notified about
      *
      * \param from
-     *   Pagination token given to retrieve the next set of events.
+     *   Pagination token to continue from. This should be the `next_token`
+     *   returned from an earlier call to this endpoint.
      *
      * \param limit
      *   Limit on the number of events to return in this request.
diff --git a/lib/csapi/openid.cpp b/lib/csapi/openid.cpp
index 5c93a2d7..7e89b8a6 100644
--- a/lib/csapi/openid.cpp
+++ b/lib/csapi/openid.cpp
@@ -9,8 +9,8 @@ using namespace Quotient;
 RequestOpenIdTokenJob::RequestOpenIdTokenJob(const QString& userId,
                                              const QJsonObject& body)
     : BaseJob(HttpVerb::Post, QStringLiteral("RequestOpenIdTokenJob"),
-              makePath("/_matrix/client/r0", "/user/", userId,
+              makePath("/_matrix/client/v3", "/user/", userId,
                        "/openid/request_token"))
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
diff --git a/lib/csapi/openid.h b/lib/csapi/openid.h
index 773b6011..b3f72a25 100644
--- a/lib/csapi/openid.h
+++ b/lib/csapi/openid.h
@@ -43,7 +43,10 @@ public:
     /// Specification](http://openid.net/specs/openid-connect-core-1_0.html#TokenResponse)
     /// with the only difference being the lack of an `id_token`. Instead,
     /// the Matrix homeserver's name is provided.
-    OpenidToken tokenData() const { return fromJson<OpenidToken>(jsonData()); }
+    OpenIdCredentials tokenData() const
+    {
+        return fromJson<OpenIdCredentials>(jsonData());
+    }
 };
 
 } // namespace Quotient
diff --git a/lib/csapi/peeking_events.cpp b/lib/csapi/peeking_events.cpp
index eb5d22fa..9dd1445e 100644
--- a/lib/csapi/peeking_events.cpp
+++ b/lib/csapi/peeking_events.cpp
@@ -20,13 +20,13 @@ QUrl PeekEventsJob::makeRequestUrl(QUrl baseUrl, const QString& from,
                                    Omittable<int> timeout, const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/events"),
+                                   makePath("/_matrix/client/v3", "/events"),
                                    queryToPeekEvents(from, timeout, roomId));
 }
 
 PeekEventsJob::PeekEventsJob(const QString& from, Omittable<int> timeout,
                              const QString& roomId)
     : BaseJob(HttpVerb::Get, QStringLiteral("PeekEventsJob"),
-              makePath("/_matrix/client/r0", "/events"),
+              makePath("/_matrix/client/v3", "/events"),
               queryToPeekEvents(from, timeout, roomId))
 {}
diff --git a/lib/csapi/peeking_events.h b/lib/csapi/peeking_events.h
index 14cb6f0b..ff688c49 100644
--- a/lib/csapi/peeking_events.h
+++ b/lib/csapi/peeking_events.h
@@ -9,7 +9,7 @@
 
 namespace Quotient {
 
-/*! \brief Listen on the event stream.
+/*! \brief Listen on the event stream of a particular room.
  *
  * This will listen for new events related to a particular room and return
  * them to the caller. This will block until an event is received, or until
@@ -24,7 +24,7 @@ namespace Quotient {
  */
 class QUOTIENT_API PeekEventsJob : public BaseJob {
 public:
-    /*! \brief Listen on the event stream.
+    /*! \brief Listen on the event stream of a particular room.
      *
      * \param from
      *   The token to stream from. This token is either from a previous
diff --git a/lib/csapi/presence.cpp b/lib/csapi/presence.cpp
index 4f77c466..828ccfb7 100644
--- a/lib/csapi/presence.cpp
+++ b/lib/csapi/presence.cpp
@@ -9,24 +9,24 @@ using namespace Quotient;
 SetPresenceJob::SetPresenceJob(const QString& userId, const QString& presence,
                                const QString& statusMsg)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetPresenceJob"),
-              makePath("/_matrix/client/r0", "/presence/", userId, "/status"))
+              makePath("/_matrix/client/v3", "/presence/", userId, "/status"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("presence"), presence);
-    addParam<IfNotEmpty>(_data, QStringLiteral("status_msg"), statusMsg);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("presence"), presence);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("status_msg"), statusMsg);
+    setRequestData({ _dataJson });
 }
 
 QUrl GetPresenceJob::makeRequestUrl(QUrl baseUrl, const QString& userId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/presence/",
+                                   makePath("/_matrix/client/v3", "/presence/",
                                             userId, "/status"));
 }
 
 GetPresenceJob::GetPresenceJob(const QString& userId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetPresenceJob"),
-              makePath("/_matrix/client/r0", "/presence/", userId, "/status"))
+              makePath("/_matrix/client/v3", "/presence/", userId, "/status"))
 {
     addExpectedKey("presence");
 }
diff --git a/lib/csapi/profile.cpp b/lib/csapi/profile.cpp
index 64ac84ca..f024ed82 100644
--- a/lib/csapi/profile.cpp
+++ b/lib/csapi/profile.cpp
@@ -9,56 +9,58 @@ using namespace Quotient;
 SetDisplayNameJob::SetDisplayNameJob(const QString& userId,
                                      const QString& displayname)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetDisplayNameJob"),
-              makePath("/_matrix/client/r0", "/profile/", userId, "/displayname"))
+              makePath("/_matrix/client/v3", "/profile/", userId,
+                       "/displayname"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("displayname"), displayname);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("displayname"), displayname);
+    setRequestData({ _dataJson });
 }
 
 QUrl GetDisplayNameJob::makeRequestUrl(QUrl baseUrl, const QString& userId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/profile/",
+                                   makePath("/_matrix/client/v3", "/profile/",
                                             userId, "/displayname"));
 }
 
 GetDisplayNameJob::GetDisplayNameJob(const QString& userId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetDisplayNameJob"),
-              makePath("/_matrix/client/r0", "/profile/", userId, "/displayname"),
+              makePath("/_matrix/client/v3", "/profile/", userId,
+                       "/displayname"),
               false)
 {}
 
 SetAvatarUrlJob::SetAvatarUrlJob(const QString& userId, const QUrl& avatarUrl)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetAvatarUrlJob"),
-              makePath("/_matrix/client/r0", "/profile/", userId, "/avatar_url"))
+              makePath("/_matrix/client/v3", "/profile/", userId, "/avatar_url"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("avatar_url"), avatarUrl);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("avatar_url"), avatarUrl);
+    setRequestData({ _dataJson });
 }
 
 QUrl GetAvatarUrlJob::makeRequestUrl(QUrl baseUrl, const QString& userId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/profile/",
+                                   makePath("/_matrix/client/v3", "/profile/",
                                             userId, "/avatar_url"));
 }
 
 GetAvatarUrlJob::GetAvatarUrlJob(const QString& userId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetAvatarUrlJob"),
-              makePath("/_matrix/client/r0", "/profile/", userId, "/avatar_url"),
+              makePath("/_matrix/client/v3", "/profile/", userId, "/avatar_url"),
               false)
 {}
 
 QUrl GetUserProfileJob::makeRequestUrl(QUrl baseUrl, const QString& userId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/profile/",
+                                   makePath("/_matrix/client/v3", "/profile/",
                                             userId));
 }
 
 GetUserProfileJob::GetUserProfileJob(const QString& userId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetUserProfileJob"),
-              makePath("/_matrix/client/r0", "/profile/", userId), false)
+              makePath("/_matrix/client/v3", "/profile/", userId), false)
 {}
diff --git a/lib/csapi/pusher.cpp b/lib/csapi/pusher.cpp
index ef4b3767..fb6595fc 100644
--- a/lib/csapi/pusher.cpp
+++ b/lib/csapi/pusher.cpp
@@ -9,12 +9,12 @@ using namespace Quotient;
 QUrl GetPushersJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/pushers"));
+                                   makePath("/_matrix/client/v3", "/pushers"));
 }
 
 GetPushersJob::GetPushersJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetPushersJob"),
-              makePath("/_matrix/client/r0", "/pushers"))
+              makePath("/_matrix/client/v3", "/pushers"))
 {}
 
 PostPusherJob::PostPusherJob(const QString& pushkey, const QString& kind,
@@ -23,17 +23,18 @@ PostPusherJob::PostPusherJob(const QString& pushkey, const QString& kind,
                              const QString& lang, const PusherData& data,
                              const QString& profileTag, Omittable<bool> append)
     : BaseJob(HttpVerb::Post, QStringLiteral("PostPusherJob"),
-              makePath("/_matrix/client/r0", "/pushers/set"))
+              makePath("/_matrix/client/v3", "/pushers/set"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("pushkey"), pushkey);
-    addParam<>(_data, QStringLiteral("kind"), kind);
-    addParam<>(_data, QStringLiteral("app_id"), appId);
-    addParam<>(_data, QStringLiteral("app_display_name"), appDisplayName);
-    addParam<>(_data, QStringLiteral("device_display_name"), deviceDisplayName);
-    addParam<IfNotEmpty>(_data, QStringLiteral("profile_tag"), profileTag);
-    addParam<>(_data, QStringLiteral("lang"), lang);
-    addParam<>(_data, QStringLiteral("data"), data);
-    addParam<IfNotEmpty>(_data, QStringLiteral("append"), append);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("pushkey"), pushkey);
+    addParam<>(_dataJson, QStringLiteral("kind"), kind);
+    addParam<>(_dataJson, QStringLiteral("app_id"), appId);
+    addParam<>(_dataJson, QStringLiteral("app_display_name"), appDisplayName);
+    addParam<>(_dataJson, QStringLiteral("device_display_name"),
+               deviceDisplayName);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("profile_tag"), profileTag);
+    addParam<>(_dataJson, QStringLiteral("lang"), lang);
+    addParam<>(_dataJson, QStringLiteral("data"), data);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("append"), append);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/pushrules.cpp b/lib/csapi/pushrules.cpp
index 0d840788..2376654a 100644
--- a/lib/csapi/pushrules.cpp
+++ b/lib/csapi/pushrules.cpp
@@ -9,12 +9,12 @@ using namespace Quotient;
 QUrl GetPushRulesJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/pushrules"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/pushrules"));
 }
 
 GetPushRulesJob::GetPushRulesJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetPushRulesJob"),
-              makePath("/_matrix/client/r0", "/pushrules"))
+              makePath("/_matrix/client/v3", "/pushrules"))
 {
     addExpectedKey("global");
 }
@@ -23,14 +23,14 @@ QUrl GetPushRuleJob::makeRequestUrl(QUrl baseUrl, const QString& scope,
                                     const QString& kind, const QString& ruleId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/pushrules/",
+                                   makePath("/_matrix/client/v3", "/pushrules/",
                                             scope, "/", kind, "/", ruleId));
 }
 
 GetPushRuleJob::GetPushRuleJob(const QString& scope, const QString& kind,
                                const QString& ruleId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetPushRuleJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId))
 {}
 
@@ -39,14 +39,14 @@ QUrl DeletePushRuleJob::makeRequestUrl(QUrl baseUrl, const QString& scope,
                                        const QString& ruleId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/pushrules/",
+                                   makePath("/_matrix/client/v3", "/pushrules/",
                                             scope, "/", kind, "/", ruleId));
 }
 
 DeletePushRuleJob::DeletePushRuleJob(const QString& scope, const QString& kind,
                                      const QString& ruleId)
     : BaseJob(HttpVerb::Delete, QStringLiteral("DeletePushRuleJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId))
 {}
 
@@ -65,15 +65,15 @@ SetPushRuleJob::SetPushRuleJob(const QString& scope, const QString& kind,
                                const QVector<PushCondition>& conditions,
                                const QString& pattern)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetPushRuleJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId),
               queryToSetPushRule(before, after))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("actions"), actions);
-    addParam<IfNotEmpty>(_data, QStringLiteral("conditions"), conditions);
-    addParam<IfNotEmpty>(_data, QStringLiteral("pattern"), pattern);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("actions"), actions);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("conditions"), conditions);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("pattern"), pattern);
+    setRequestData({ _dataJson });
 }
 
 QUrl IsPushRuleEnabledJob::makeRequestUrl(QUrl baseUrl, const QString& scope,
@@ -81,7 +81,7 @@ QUrl IsPushRuleEnabledJob::makeRequestUrl(QUrl baseUrl, const QString& scope,
                                           const QString& ruleId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/pushrules/",
+                                   makePath("/_matrix/client/v3", "/pushrules/",
                                             scope, "/", kind, "/", ruleId,
                                             "/enabled"));
 }
@@ -90,7 +90,7 @@ IsPushRuleEnabledJob::IsPushRuleEnabledJob(const QString& scope,
                                            const QString& kind,
                                            const QString& ruleId)
     : BaseJob(HttpVerb::Get, QStringLiteral("IsPushRuleEnabledJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId, "/enabled"))
 {
     addExpectedKey("enabled");
@@ -100,12 +100,12 @@ SetPushRuleEnabledJob::SetPushRuleEnabledJob(const QString& scope,
                                              const QString& kind,
                                              const QString& ruleId, bool enabled)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetPushRuleEnabledJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId, "/enabled"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("enabled"), enabled);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("enabled"), enabled);
+    setRequestData({ _dataJson });
 }
 
 QUrl GetPushRuleActionsJob::makeRequestUrl(QUrl baseUrl, const QString& scope,
@@ -113,7 +113,7 @@ QUrl GetPushRuleActionsJob::makeRequestUrl(QUrl baseUrl, const QString& scope,
                                            const QString& ruleId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/pushrules/",
+                                   makePath("/_matrix/client/v3", "/pushrules/",
                                             scope, "/", kind, "/", ruleId,
                                             "/actions"));
 }
@@ -122,7 +122,7 @@ GetPushRuleActionsJob::GetPushRuleActionsJob(const QString& scope,
                                              const QString& kind,
                                              const QString& ruleId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetPushRuleActionsJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId, "/actions"))
 {
     addExpectedKey("actions");
@@ -133,10 +133,10 @@ SetPushRuleActionsJob::SetPushRuleActionsJob(const QString& scope,
                                              const QString& ruleId,
                                              const QVector<QVariant>& actions)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetPushRuleActionsJob"),
-              makePath("/_matrix/client/r0", "/pushrules/", scope, "/", kind,
+              makePath("/_matrix/client/v3", "/pushrules/", scope, "/", kind,
                        "/", ruleId, "/actions"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("actions"), actions);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("actions"), actions);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/read_markers.cpp b/lib/csapi/read_markers.cpp
index f2edb71e..de5f4a9a 100644
--- a/lib/csapi/read_markers.cpp
+++ b/lib/csapi/read_markers.cpp
@@ -10,10 +10,10 @@ SetReadMarkerJob::SetReadMarkerJob(const QString& roomId,
                                    const QString& mFullyRead,
                                    const QString& mRead)
     : BaseJob(HttpVerb::Post, QStringLiteral("SetReadMarkerJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/read_markers"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/read_markers"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("m.fully_read"), mFullyRead);
-    addParam<IfNotEmpty>(_data, QStringLiteral("m.read"), mRead);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("m.fully_read"), mFullyRead);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("m.read"), mRead);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/receipts.cpp b/lib/csapi/receipts.cpp
index 401c3bfe..0194603d 100644
--- a/lib/csapi/receipts.cpp
+++ b/lib/csapi/receipts.cpp
@@ -10,8 +10,8 @@ PostReceiptJob::PostReceiptJob(const QString& roomId, const QString& receiptType
                                const QString& eventId,
                                const QJsonObject& receipt)
     : BaseJob(HttpVerb::Post, QStringLiteral("PostReceiptJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/receipt/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/receipt/",
                        receiptType, "/", eventId))
 {
-    setRequestData(RequestData(toJson(receipt)));
+    setRequestData({ toJson(receipt) });
 }
diff --git a/lib/csapi/redaction.cpp b/lib/csapi/redaction.cpp
index acf1b0e4..154abd9b 100644
--- a/lib/csapi/redaction.cpp
+++ b/lib/csapi/redaction.cpp
@@ -9,10 +9,10 @@ using namespace Quotient;
 RedactEventJob::RedactEventJob(const QString& roomId, const QString& eventId,
                                const QString& txnId, const QString& reason)
     : BaseJob(HttpVerb::Put, QStringLiteral("RedactEventJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/redact/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/redact/",
                        eventId, "/", txnId))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/refresh.cpp b/lib/csapi/refresh.cpp
new file mode 100644
index 00000000..284ae4ff
--- /dev/null
+++ b/lib/csapi/refresh.cpp
@@ -0,0 +1,18 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#include "refresh.h"
+
+using namespace Quotient;
+
+RefreshJob::RefreshJob(const QString& refreshToken)
+    : BaseJob(HttpVerb::Post, QStringLiteral("RefreshJob"),
+              makePath("/_matrix/client/v3", "/refresh"), false)
+{
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("refresh_token"),
+                         refreshToken);
+    setRequestData({ _dataJson });
+    addExpectedKey("access_token");
+}
diff --git a/lib/csapi/refresh.h b/lib/csapi/refresh.h
new file mode 100644
index 00000000..d432802c
--- /dev/null
+++ b/lib/csapi/refresh.h
@@ -0,0 +1,65 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#pragma once
+
+#include "jobs/basejob.h"
+
+namespace Quotient {
+
+/*! \brief Refresh an access token
+ *
+ * Refresh an access token. Clients should use the returned access token
+ * when making subsequent API calls, and store the returned refresh token
+ * (if given) in order to refresh the new access token when necessary.
+ *
+ * After an access token has been refreshed, a server can choose to
+ * invalidate the old access token immediately, or can choose not to, for
+ * example if the access token would expire soon anyways. Clients should
+ * not make any assumptions about the old access token still being valid,
+ * and should use the newly provided access token instead.
+ *
+ * The old refresh token remains valid until the new access token or refresh
+ * token is used, at which point the old refresh token is revoked.
+ *
+ * Note that this endpoint does not require authentication via an
+ * access token. Authentication is provided via the refresh token.
+ *
+ * Application Service identity assertion is disabled for this endpoint.
+ */
+class QUOTIENT_API RefreshJob : public BaseJob {
+public:
+    /*! \brief Refresh an access token
+     *
+     * \param refreshToken
+     *   The refresh token
+     */
+    explicit RefreshJob(const QString& refreshToken = {});
+
+    // Result properties
+
+    /// The new access token to use.
+    QString accessToken() const
+    {
+        return loadFromJson<QString>("access_token"_ls);
+    }
+
+    /// The new refresh token to use when the access token needs to
+    /// be refreshed again. If not given, the old refresh token can
+    /// be re-used.
+    QString refreshToken() const
+    {
+        return loadFromJson<QString>("refresh_token"_ls);
+    }
+
+    /// The lifetime of the access token, in milliseconds. If not
+    /// given, the client can assume that the access token will not
+    /// expire.
+    Omittable<int> expiresInMs() const
+    {
+        return loadFromJson<Omittable<int>>("expires_in_ms"_ls);
+    }
+};
+
+} // namespace Quotient
diff --git a/lib/csapi/registration.cpp b/lib/csapi/registration.cpp
index 153abcee..04c0fe12 100644
--- a/lib/csapi/registration.cpp
+++ b/lib/csapi/registration.cpp
@@ -18,85 +18,91 @@ RegisterJob::RegisterJob(const QString& kind,
                          const QString& username, const QString& password,
                          const QString& deviceId,
                          const QString& initialDeviceDisplayName,
-                         Omittable<bool> inhibitLogin)
+                         Omittable<bool> inhibitLogin,
+                         Omittable<bool> refreshToken)
     : BaseJob(HttpVerb::Post, QStringLiteral("RegisterJob"),
-              makePath("/_matrix/client/r0", "/register"),
+              makePath("/_matrix/client/v3", "/register"),
               queryToRegister(kind), {}, false)
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("auth"), auth);
-    addParam<IfNotEmpty>(_data, QStringLiteral("username"), username);
-    addParam<IfNotEmpty>(_data, QStringLiteral("password"), password);
-    addParam<IfNotEmpty>(_data, QStringLiteral("device_id"), deviceId);
-    addParam<IfNotEmpty>(_data, QStringLiteral("initial_device_display_name"),
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("username"), username);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("password"), password);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("device_id"), deviceId);
+    addParam<IfNotEmpty>(_dataJson,
+                         QStringLiteral("initial_device_display_name"),
                          initialDeviceDisplayName);
-    addParam<IfNotEmpty>(_data, QStringLiteral("inhibit_login"), inhibitLogin);
-    setRequestData(std::move(_data));
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("inhibit_login"),
+                         inhibitLogin);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("refresh_token"),
+                         refreshToken);
+    setRequestData({ _dataJson });
     addExpectedKey("user_id");
 }
 
 RequestTokenToRegisterEmailJob::RequestTokenToRegisterEmailJob(
     const EmailValidationData& body)
     : BaseJob(HttpVerb::Post, QStringLiteral("RequestTokenToRegisterEmailJob"),
-              makePath("/_matrix/client/r0", "/register/email/requestToken"),
+              makePath("/_matrix/client/v3", "/register/email/requestToken"),
               false)
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
 
 RequestTokenToRegisterMSISDNJob::RequestTokenToRegisterMSISDNJob(
     const MsisdnValidationData& body)
     : BaseJob(HttpVerb::Post, QStringLiteral("RequestTokenToRegisterMSISDNJob"),
-              makePath("/_matrix/client/r0", "/register/msisdn/requestToken"),
+              makePath("/_matrix/client/v3", "/register/msisdn/requestToken"),
               false)
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
 
 ChangePasswordJob::ChangePasswordJob(const QString& newPassword,
                                      bool logoutDevices,
                                      const Omittable<AuthenticationData>& auth)
     : BaseJob(HttpVerb::Post, QStringLiteral("ChangePasswordJob"),
-              makePath("/_matrix/client/r0", "/account/password"))
+              makePath("/_matrix/client/v3", "/account/password"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("new_password"), newPassword);
-    addParam<IfNotEmpty>(_data, QStringLiteral("logout_devices"), logoutDevices);
-    addParam<IfNotEmpty>(_data, QStringLiteral("auth"), auth);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("new_password"), newPassword);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("logout_devices"),
+                         logoutDevices);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    setRequestData({ _dataJson });
 }
 
 RequestTokenToResetPasswordEmailJob::RequestTokenToResetPasswordEmailJob(
     const EmailValidationData& body)
     : BaseJob(HttpVerb::Post,
               QStringLiteral("RequestTokenToResetPasswordEmailJob"),
-              makePath("/_matrix/client/r0",
+              makePath("/_matrix/client/v3",
                        "/account/password/email/requestToken"),
               false)
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
 
 RequestTokenToResetPasswordMSISDNJob::RequestTokenToResetPasswordMSISDNJob(
     const MsisdnValidationData& body)
     : BaseJob(HttpVerb::Post,
               QStringLiteral("RequestTokenToResetPasswordMSISDNJob"),
-              makePath("/_matrix/client/r0",
+              makePath("/_matrix/client/v3",
                        "/account/password/msisdn/requestToken"),
               false)
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
 }
 
 DeactivateAccountJob::DeactivateAccountJob(
     const Omittable<AuthenticationData>& auth, const QString& idServer)
     : BaseJob(HttpVerb::Post, QStringLiteral("DeactivateAccountJob"),
-              makePath("/_matrix/client/r0", "/account/deactivate"))
+              makePath("/_matrix/client/v3", "/account/deactivate"))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("auth"), auth);
-    addParam<IfNotEmpty>(_data, QStringLiteral("id_server"), idServer);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("auth"), auth);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("id_server"), idServer);
+    setRequestData({ _dataJson });
     addExpectedKey("id_server_unbind_result");
 }
 
@@ -111,13 +117,14 @@ QUrl CheckUsernameAvailabilityJob::makeRequestUrl(QUrl baseUrl,
                                                   const QString& username)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/register/available"),
                                    queryToCheckUsernameAvailability(username));
 }
 
-CheckUsernameAvailabilityJob::CheckUsernameAvailabilityJob(const QString& username)
+CheckUsernameAvailabilityJob::CheckUsernameAvailabilityJob(
+    const QString& username)
     : BaseJob(HttpVerb::Get, QStringLiteral("CheckUsernameAvailabilityJob"),
-              makePath("/_matrix/client/r0", "/register/available"),
+              makePath("/_matrix/client/v3", "/register/available"),
               queryToCheckUsernameAvailability(username), {}, false)
 {}
diff --git a/lib/csapi/registration.h b/lib/csapi/registration.h
index 10375971..21d7f9d7 100644
--- a/lib/csapi/registration.h
+++ b/lib/csapi/registration.h
@@ -93,6 +93,9 @@ public:
      *   If true, an `access_token` and `device_id` should not be
      *   returned from this call, therefore preventing an automatic
      *   login. Defaults to false.
+     *
+     * \param refreshToken
+     *   If true, the client supports refresh tokens.
      */
     explicit RegisterJob(const QString& kind = QStringLiteral("user"),
                          const Omittable<AuthenticationData>& auth = none,
@@ -100,7 +103,8 @@ public:
                          const QString& password = {},
                          const QString& deviceId = {},
                          const QString& initialDeviceDisplayName = {},
-                         Omittable<bool> inhibitLogin = none);
+                         Omittable<bool> inhibitLogin = none,
+                         Omittable<bool> refreshToken = none);
 
     // Result properties
 
@@ -118,15 +122,27 @@ public:
         return loadFromJson<QString>("access_token"_ls);
     }
 
-    /// The server_name of the homeserver on which the account has
-    /// been registered.
+    /// A refresh token for the account. This token can be used to
+    /// obtain a new access token when it expires by calling the
+    /// `/refresh` endpoint.
+    ///
+    /// Omitted if the `inhibit_login` option is true.
+    QString refreshToken() const
+    {
+        return loadFromJson<QString>("refresh_token"_ls);
+    }
+
+    /// The lifetime of the access token, in milliseconds. Once
+    /// the access token has expired a new access token can be
+    /// obtained by using the provided refresh token. If no
+    /// refresh token is provided, the client will need to re-log in
+    /// to obtain a new access token. If not given, the client can
+    /// assume that the access token will not expire.
     ///
-    /// **Deprecated**. Clients should extract the server_name from
-    /// `user_id` (by splitting at the first colon) if they require
-    /// it. Note also that `homeserver` is not spelt this way.
-    QString homeServer() const
+    /// Omitted if the `inhibit_login` option is true.
+    Omittable<int> expiresInMs() const
     {
-        return loadFromJson<QString>("home_server"_ls);
+        return loadFromJson<Omittable<int>>("expires_in_ms"_ls);
     }
 
     /// ID of the registered device. Will be the same as the
@@ -227,7 +243,8 @@ public:
      * should be revoked if the request succeeds.
      *
      *   When `false`, the server can still take advantage of the [soft logout
-     * method](/client-server-api/#soft-logout) for the user's remaining devices.
+     * method](/client-server-api/#soft-logout) for the user's remaining
+     * devices.
      *
      * \param auth
      *   Additional authentication information for the user-interactive
@@ -247,7 +264,7 @@ public:
  * `/account/password` endpoint.
  *
  * This API's parameters and response are identical to that of the
- * [`/register/email/requestToken`](/client-server-api/#post_matrixclientr0registeremailrequesttoken)
+ * [`/register/email/requestToken`](/client-server-api/#post_matrixclientv3registeremailrequesttoken)
  * endpoint, except that
  * `M_THREEPID_NOT_FOUND` may be returned if no account matching the
  * given email address could be found. The server may instead send an
@@ -269,7 +286,7 @@ public:
      *   `/account/password` endpoint.
      *
      *   This API's parameters and response are identical to that of the
-     *   [`/register/email/requestToken`](/client-server-api/#post_matrixclientr0registeremailrequesttoken)
+     *   [`/register/email/requestToken`](/client-server-api/#post_matrixclientv3registeremailrequesttoken)
      *   endpoint, except that
      *   `M_THREEPID_NOT_FOUND` may be returned if no account matching the
      *   given email address could be found. The server may instead send an
@@ -299,7 +316,7 @@ public:
  * `/account/password` endpoint.
  *
  * This API's parameters and response are identical to that of the
- * [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientr0registermsisdnrequesttoken)
+ * [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientv3registermsisdnrequesttoken)
  * endpoint, except that
  * `M_THREEPID_NOT_FOUND` may be returned if no account matching the
  * given phone number could be found. The server may instead send the SMS
@@ -321,15 +338,16 @@ public:
      *   `/account/password` endpoint.
      *
      *   This API's parameters and response are identical to that of the
-     *   [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientr0registermsisdnrequesttoken)
+     *   [`/register/msisdn/requestToken`](/client-server-api/#post_matrixclientv3registermsisdnrequesttoken)
      *   endpoint, except that
      *   `M_THREEPID_NOT_FOUND` may be returned if no account matching the
      *   given phone number could be found. The server may instead send the SMS
      *   to the given phone number prompting the user to create an account.
      *   `M_THREEPID_IN_USE` may not be returned.
      *
-     *   The homeserver should validate the phone number itself, either by sending
-     * a validation message itself or by using a service it has control over.
+     *   The homeserver should validate the phone number itself, either by
+     * sending a validation message itself or by using a service it has control
+     * over.
      */
     explicit RequestTokenToResetPasswordMSISDNJob(
         const MsisdnValidationData& body);
@@ -377,8 +395,9 @@ public:
      *   it must return an `id_server_unbind_result` of
      *   `no-support`.
      */
-    explicit DeactivateAccountJob(const Omittable<AuthenticationData>& auth = none,
-                                  const QString& idServer = {});
+    explicit DeactivateAccountJob(
+        const Omittable<AuthenticationData>& auth = none,
+        const QString& idServer = {});
 
     // Result properties
 
diff --git a/lib/csapi/registration_tokens.cpp b/lib/csapi/registration_tokens.cpp
new file mode 100644
index 00000000..9c1f0587
--- /dev/null
+++ b/lib/csapi/registration_tokens.cpp
@@ -0,0 +1,33 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#include "registration_tokens.h"
+
+using namespace Quotient;
+
+auto queryToRegistrationTokenValidity(const QString& token)
+{
+    QUrlQuery _q;
+    addParam<>(_q, QStringLiteral("token"), token);
+    return _q;
+}
+
+QUrl RegistrationTokenValidityJob::makeRequestUrl(QUrl baseUrl,
+                                                  const QString& token)
+{
+    return BaseJob::makeRequestUrl(
+        std::move(baseUrl),
+        makePath("/_matrix/client/v1",
+                 "/register/m.login.registration_token/validity"),
+        queryToRegistrationTokenValidity(token));
+}
+
+RegistrationTokenValidityJob::RegistrationTokenValidityJob(const QString& token)
+    : BaseJob(HttpVerb::Get, QStringLiteral("RegistrationTokenValidityJob"),
+              makePath("/_matrix/client/v1",
+                       "/register/m.login.registration_token/validity"),
+              queryToRegistrationTokenValidity(token), {}, false)
+{
+    addExpectedKey("valid");
+}
diff --git a/lib/csapi/registration_tokens.h b/lib/csapi/registration_tokens.h
new file mode 100644
index 00000000..e3008dd4
--- /dev/null
+++ b/lib/csapi/registration_tokens.h
@@ -0,0 +1,44 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#pragma once
+
+#include "jobs/basejob.h"
+
+namespace Quotient {
+
+/*! \brief Query if a given registration token is still valid.
+ *
+ * Queries the server to determine if a given registration token is still
+ * valid at the time of request. This is a point-in-time check where the
+ * token might still expire by the time it is used.
+ *
+ * Servers should be sure to rate limit this endpoint to avoid brute force
+ * attacks.
+ */
+class QUOTIENT_API RegistrationTokenValidityJob : public BaseJob {
+public:
+    /*! \brief Query if a given registration token is still valid.
+     *
+     * \param token
+     *   The token to check validity of.
+     */
+    explicit RegistrationTokenValidityJob(const QString& token);
+
+    /*! \brief Construct a URL without creating a full-fledged job object
+     *
+     * This function can be used when a URL for RegistrationTokenValidityJob
+     * is necessary but the job itself isn't.
+     */
+    static QUrl makeRequestUrl(QUrl baseUrl, const QString& token);
+
+    // Result properties
+
+    /// True if the token is still valid, false otherwise. This should
+    /// additionally be false if the token is not a recognised token by
+    /// the server.
+    bool valid() const { return loadFromJson<bool>("valid"_ls); }
+};
+
+} // namespace Quotient
diff --git a/lib/csapi/relations.cpp b/lib/csapi/relations.cpp
new file mode 100644
index 00000000..8bcecee4
--- /dev/null
+++ b/lib/csapi/relations.cpp
@@ -0,0 +1,111 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#include "relations.h"
+
+using namespace Quotient;
+
+auto queryToGetRelatingEvents(const QString& from, const QString& to,
+                              Omittable<int> limit)
+{
+    QUrlQuery _q;
+    addParam<IfNotEmpty>(_q, QStringLiteral("from"), from);
+    addParam<IfNotEmpty>(_q, QStringLiteral("to"), to);
+    addParam<IfNotEmpty>(_q, QStringLiteral("limit"), limit);
+    return _q;
+}
+
+QUrl GetRelatingEventsJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
+                                          const QString& eventId,
+                                          const QString& from, const QString& to,
+                                          Omittable<int> limit)
+{
+    return BaseJob::makeRequestUrl(std::move(baseUrl),
+                                   makePath("/_matrix/client/v1", "/rooms/",
+                                            roomId, "/relations/", eventId),
+                                   queryToGetRelatingEvents(from, to, limit));
+}
+
+GetRelatingEventsJob::GetRelatingEventsJob(const QString& roomId,
+                                           const QString& eventId,
+                                           const QString& from,
+                                           const QString& to,
+                                           Omittable<int> limit)
+    : BaseJob(HttpVerb::Get, QStringLiteral("GetRelatingEventsJob"),
+              makePath("/_matrix/client/v1", "/rooms/", roomId, "/relations/",
+                       eventId),
+              queryToGetRelatingEvents(from, to, limit))
+{
+    addExpectedKey("chunk");
+}
+
+auto queryToGetRelatingEventsWithRelType(const QString& from, const QString& to,
+                                         Omittable<int> limit)
+{
+    QUrlQuery _q;
+    addParam<IfNotEmpty>(_q, QStringLiteral("from"), from);
+    addParam<IfNotEmpty>(_q, QStringLiteral("to"), to);
+    addParam<IfNotEmpty>(_q, QStringLiteral("limit"), limit);
+    return _q;
+}
+
+QUrl GetRelatingEventsWithRelTypeJob::makeRequestUrl(
+    QUrl baseUrl, const QString& roomId, const QString& eventId,
+    const QString& relType, const QString& from, const QString& to,
+    Omittable<int> limit)
+{
+    return BaseJob::makeRequestUrl(
+        std::move(baseUrl),
+        makePath("/_matrix/client/v1", "/rooms/", roomId, "/relations/",
+                 eventId, "/", relType),
+        queryToGetRelatingEventsWithRelType(from, to, limit));
+}
+
+GetRelatingEventsWithRelTypeJob::GetRelatingEventsWithRelTypeJob(
+    const QString& roomId, const QString& eventId, const QString& relType,
+    const QString& from, const QString& to, Omittable<int> limit)
+    : BaseJob(HttpVerb::Get, QStringLiteral("GetRelatingEventsWithRelTypeJob"),
+              makePath("/_matrix/client/v1", "/rooms/", roomId, "/relations/",
+                       eventId, "/", relType),
+              queryToGetRelatingEventsWithRelType(from, to, limit))
+{
+    addExpectedKey("chunk");
+}
+
+auto queryToGetRelatingEventsWithRelTypeAndEventType(const QString& from,
+                                                     const QString& to,
+                                                     Omittable<int> limit)
+{
+    QUrlQuery _q;
+    addParam<IfNotEmpty>(_q, QStringLiteral("from"), from);
+    addParam<IfNotEmpty>(_q, QStringLiteral("to"), to);
+    addParam<IfNotEmpty>(_q, QStringLiteral("limit"), limit);
+    return _q;
+}
+
+QUrl GetRelatingEventsWithRelTypeAndEventTypeJob::makeRequestUrl(
+    QUrl baseUrl, const QString& roomId, const QString& eventId,
+    const QString& relType, const QString& eventType, const QString& from,
+    const QString& to, Omittable<int> limit)
+{
+    return BaseJob::makeRequestUrl(
+        std::move(baseUrl),
+        makePath("/_matrix/client/v1", "/rooms/", roomId, "/relations/",
+                 eventId, "/", relType, "/", eventType),
+        queryToGetRelatingEventsWithRelTypeAndEventType(from, to, limit));
+}
+
+GetRelatingEventsWithRelTypeAndEventTypeJob::
+    GetRelatingEventsWithRelTypeAndEventTypeJob(
+        const QString& roomId, const QString& eventId, const QString& relType,
+        const QString& eventType, const QString& from, const QString& to,
+        Omittable<int> limit)
+    : BaseJob(HttpVerb::Get,
+              QStringLiteral("GetRelatingEventsWithRelTypeAndEventTypeJob"),
+              makePath("/_matrix/client/v1", "/rooms/", roomId, "/relations/",
+                       eventId, "/", relType, "/", eventType),
+              queryToGetRelatingEventsWithRelTypeAndEventType(from, to, limit))
+{
+    addExpectedKey("chunk");
+}
diff --git a/lib/csapi/relations.h b/lib/csapi/relations.h
new file mode 100644
index 00000000..985a43b5
--- /dev/null
+++ b/lib/csapi/relations.h
@@ -0,0 +1,277 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#pragma once
+
+#include "events/eventloader.h"
+#include "jobs/basejob.h"
+
+namespace Quotient {
+
+/*! \brief Get the child events for a given parent event.
+ *
+ * Retrieve all of the child events for a given parent event.
+ *
+ * Note that when paginating the `from` token should be "after" the `to` token
+ * in terms of topological ordering, because it is only possible to paginate
+ * "backwards" through events, starting at `from`.
+ *
+ * For example, passing a `from` token from page 2 of the results, and a `to`
+ * token from page 1, would return the empty set. The caller can use a `from`
+ * token from page 1 and a `to` token from page 2 to paginate over the same
+ * range, however.
+ */
+class QUOTIENT_API GetRelatingEventsJob : public BaseJob {
+public:
+    /*! \brief Get the child events for a given parent event.
+     *
+     * \param roomId
+     *   The ID of the room containing the parent event.
+     *
+     * \param eventId
+     *   The ID of the parent event whose child events are to be returned.
+     *
+     * \param from
+     *   The pagination token to start returning results from. If not supplied,
+     * results start at the most recent topological event known to the server.
+     *
+     *   Can be a `next_batch` token from a previous call, or a returned
+     *   `start` token from
+     * [`/messages`](/client-server-api/#get_matrixclientv3roomsroomidmessages),
+     *   or a `next_batch` token from
+     * [`/sync`](/client-server-api/#get_matrixclientv3sync).
+     *
+     * \param to
+     *   The pagination token to stop returning results at. If not supplied,
+     * results continue up to `limit` or until there are no more events.
+     *
+     *   Like `from`, this can be a previous token from a prior call to this
+     * endpoint or from `/messages` or `/sync`.
+     *
+     * \param limit
+     *   The maximum number of results to return in a single `chunk`. The server
+     * can and should apply a maximum value to this parameter to avoid large
+     * responses.
+     *
+     *   Similarly, the server should apply a default value when not supplied.
+     */
+    explicit GetRelatingEventsJob(const QString& roomId, const QString& eventId,
+                                  const QString& from = {},
+                                  const QString& to = {},
+                                  Omittable<int> limit = none);
+
+    /*! \brief Construct a URL without creating a full-fledged job object
+     *
+     * This function can be used when a URL for GetRelatingEventsJob
+     * is necessary but the job itself isn't.
+     */
+    static QUrl makeRequestUrl(QUrl baseUrl, const QString& roomId,
+                               const QString& eventId, const QString& from = {},
+                               const QString& to = {},
+                               Omittable<int> limit = none);
+
+    // Result properties
+
+    /// The child events of the requested event, ordered topologically
+    /// most-recent first.
+    RoomEvents chunk() { return takeFromJson<RoomEvents>("chunk"_ls); }
+
+    /// An opaque string representing a pagination token. The absence of this
+    /// token means there are no more results to fetch and the client should
+    /// stop paginating.
+    QString nextBatch() const { return loadFromJson<QString>("next_batch"_ls); }
+
+    /// An opaque string representing a pagination token. The absence of this
+    /// token means this is the start of the result set, i.e. this is the first
+    /// batch/page.
+    QString prevBatch() const { return loadFromJson<QString>("prev_batch"_ls); }
+};
+
+/*! \brief Get the child events for a given parent event, with a given
+ * `relType`.
+ *
+ * Retrieve all of the child events for a given parent event which relate to the
+ * parent using the given `relType`.
+ *
+ * Note that when paginating the `from` token should be "after" the `to` token
+ * in terms of topological ordering, because it is only possible to paginate
+ * "backwards" through events, starting at `from`.
+ *
+ * For example, passing a `from` token from page 2 of the results, and a `to`
+ * token from page 1, would return the empty set. The caller can use a `from`
+ * token from page 1 and a `to` token from page 2 to paginate over the same
+ * range, however.
+ */
+class QUOTIENT_API GetRelatingEventsWithRelTypeJob : public BaseJob {
+public:
+    /*! \brief Get the child events for a given parent event, with a given
+     * `relType`.
+     *
+     * \param roomId
+     *   The ID of the room containing the parent event.
+     *
+     * \param eventId
+     *   The ID of the parent event whose child events are to be returned.
+     *
+     * \param relType
+     *   The [relationship type](/client-server-api/#relationship-types) to
+     * search for.
+     *
+     * \param from
+     *   The pagination token to start returning results from. If not supplied,
+     * results start at the most recent topological event known to the server.
+     *
+     *   Can be a `next_batch` token from a previous call, or a returned
+     *   `start` token from
+     * [`/messages`](/client-server-api/#get_matrixclientv3roomsroomidmessages),
+     *   or a `next_batch` token from
+     * [`/sync`](/client-server-api/#get_matrixclientv3sync).
+     *
+     * \param to
+     *   The pagination token to stop returning results at. If not supplied,
+     * results continue up to `limit` or until there are no more events.
+     *
+     *   Like `from`, this can be a previous token from a prior call to this
+     * endpoint or from `/messages` or `/sync`.
+     *
+     * \param limit
+     *   The maximum number of results to return in a single `chunk`. The server
+     * can and should apply a maximum value to this parameter to avoid large
+     * responses.
+     *
+     *   Similarly, the server should apply a default value when not supplied.
+     */
+    explicit GetRelatingEventsWithRelTypeJob(const QString& roomId,
+                                             const QString& eventId,
+                                             const QString& relType,
+                                             const QString& from = {},
+                                             const QString& to = {},
+                                             Omittable<int> limit = none);
+
+    /*! \brief Construct a URL without creating a full-fledged job object
+     *
+     * This function can be used when a URL for GetRelatingEventsWithRelTypeJob
+     * is necessary but the job itself isn't.
+     */
+    static QUrl makeRequestUrl(QUrl baseUrl, const QString& roomId,
+                               const QString& eventId, const QString& relType,
+                               const QString& from = {}, const QString& to = {},
+                               Omittable<int> limit = none);
+
+    // Result properties
+
+    /// The child events of the requested event, ordered topologically
+    /// most-recent first. The events returned will match the `relType`
+    /// supplied in the URL.
+    RoomEvents chunk() { return takeFromJson<RoomEvents>("chunk"_ls); }
+
+    /// An opaque string representing a pagination token. The absence of this
+    /// token means there are no more results to fetch and the client should
+    /// stop paginating.
+    QString nextBatch() const { return loadFromJson<QString>("next_batch"_ls); }
+
+    /// An opaque string representing a pagination token. The absence of this
+    /// token means this is the start of the result set, i.e. this is the first
+    /// batch/page.
+    QString prevBatch() const { return loadFromJson<QString>("prev_batch"_ls); }
+};
+
+/*! \brief Get the child events for a given parent event, with a given `relType`
+ * and `eventType`.
+ *
+ * Retrieve all of the child events for a given parent event which relate to the
+ * parent using the given `relType` and have the given `eventType`.
+ *
+ * Note that when paginating the `from` token should be "after" the `to` token
+ * in terms of topological ordering, because it is only possible to paginate
+ * "backwards" through events, starting at `from`.
+ *
+ * For example, passing a `from` token from page 2 of the results, and a `to`
+ * token from page 1, would return the empty set. The caller can use a `from`
+ * token from page 1 and a `to` token from page 2 to paginate over the same
+ * range, however.
+ */
+class QUOTIENT_API GetRelatingEventsWithRelTypeAndEventTypeJob
+    : public BaseJob {
+public:
+    /*! \brief Get the child events for a given parent event, with a given
+     * `relType` and `eventType`.
+     *
+     * \param roomId
+     *   The ID of the room containing the parent event.
+     *
+     * \param eventId
+     *   The ID of the parent event whose child events are to be returned.
+     *
+     * \param relType
+     *   The [relationship type](/client-server-api/#relationship-types) to
+     * search for.
+     *
+     * \param eventType
+     *   The event type of child events to search for.
+     *
+     *   Note that in encrypted rooms this will typically always be
+     * `m.room.encrypted` regardless of the event type contained within the
+     * encrypted payload.
+     *
+     * \param from
+     *   The pagination token to start returning results from. If not supplied,
+     * results start at the most recent topological event known to the server.
+     *
+     *   Can be a `next_batch` token from a previous call, or a returned
+     *   `start` token from
+     * [`/messages`](/client-server-api/#get_matrixclientv3roomsroomidmessages),
+     *   or a `next_batch` token from
+     * [`/sync`](/client-server-api/#get_matrixclientv3sync).
+     *
+     * \param to
+     *   The pagination token to stop returning results at. If not supplied,
+     * results continue up to `limit` or until there are no more events.
+     *
+     *   Like `from`, this can be a previous token from a prior call to this
+     * endpoint or from `/messages` or `/sync`.
+     *
+     * \param limit
+     *   The maximum number of results to return in a single `chunk`. The server
+     * can and should apply a maximum value to this parameter to avoid large
+     * responses.
+     *
+     *   Similarly, the server should apply a default value when not supplied.
+     */
+    explicit GetRelatingEventsWithRelTypeAndEventTypeJob(
+        const QString& roomId, const QString& eventId, const QString& relType,
+        const QString& eventType, const QString& from = {},
+        const QString& to = {}, Omittable<int> limit = none);
+
+    /*! \brief Construct a URL without creating a full-fledged job object
+     *
+     * This function can be used when a URL for
+     * GetRelatingEventsWithRelTypeAndEventTypeJob is necessary but the job
+     * itself isn't.
+     */
+    static QUrl makeRequestUrl(QUrl baseUrl, const QString& roomId,
+                               const QString& eventId, const QString& relType,
+                               const QString& eventType,
+                               const QString& from = {}, const QString& to = {},
+                               Omittable<int> limit = none);
+
+    // Result properties
+
+    /// The child events of the requested event, ordered topologically
+    /// most-recent first. The events returned will match the `relType` and
+    /// `eventType` supplied in the URL.
+    RoomEvents chunk() { return takeFromJson<RoomEvents>("chunk"_ls); }
+
+    /// An opaque string representing a pagination token. The absence of this
+    /// token means there are no more results to fetch and the client should
+    /// stop paginating.
+    QString nextBatch() const { return loadFromJson<QString>("next_batch"_ls); }
+
+    /// An opaque string representing a pagination token. The absence of this
+    /// token means this is the start of the result set, i.e. this is the first
+    /// batch/page.
+    QString prevBatch() const { return loadFromJson<QString>("prev_batch"_ls); }
+};
+
+} // namespace Quotient
diff --git a/lib/csapi/report_content.cpp b/lib/csapi/report_content.cpp
index 0a76d5b8..bc52208f 100644
--- a/lib/csapi/report_content.cpp
+++ b/lib/csapi/report_content.cpp
@@ -9,11 +9,11 @@ using namespace Quotient;
 ReportContentJob::ReportContentJob(const QString& roomId, const QString& eventId,
                                    Omittable<int> score, const QString& reason)
     : BaseJob(HttpVerb::Post, QStringLiteral("ReportContentJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/report/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/report/",
                        eventId))
 {
-    QJsonObject _data;
-    addParam<IfNotEmpty>(_data, QStringLiteral("score"), score);
-    addParam<IfNotEmpty>(_data, QStringLiteral("reason"), reason);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("score"), score);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("reason"), reason);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/room_send.cpp b/lib/csapi/room_send.cpp
index f80f9300..2319496f 100644
--- a/lib/csapi/room_send.cpp
+++ b/lib/csapi/room_send.cpp
@@ -9,9 +9,9 @@ using namespace Quotient;
 SendMessageJob::SendMessageJob(const QString& roomId, const QString& eventType,
                                const QString& txnId, const QJsonObject& body)
     : BaseJob(HttpVerb::Put, QStringLiteral("SendMessageJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/send/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/send/",
                        eventType, "/", txnId))
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
     addExpectedKey("event_id");
 }
diff --git a/lib/csapi/room_send.h b/lib/csapi/room_send.h
index fea3d59d..fcb6b24f 100644
--- a/lib/csapi/room_send.h
+++ b/lib/csapi/room_send.h
@@ -16,7 +16,8 @@ namespace Quotient {
  *
  * The body of the request should be the content object of the event; the
  * fields in this object will vary depending on the type of event. See
- * [Room Events](/client-server-api/#room-events) for the m. event specification.
+ * [Room Events](/client-server-api/#room-events) for the m. event
+ * specification.
  */
 class QUOTIENT_API SendMessageJob : public BaseJob {
 public:
diff --git a/lib/csapi/room_state.cpp b/lib/csapi/room_state.cpp
index f6d2e6ec..b4adb739 100644
--- a/lib/csapi/room_state.cpp
+++ b/lib/csapi/room_state.cpp
@@ -11,9 +11,9 @@ SetRoomStateWithKeyJob::SetRoomStateWithKeyJob(const QString& roomId,
                                                const QString& stateKey,
                                                const QJsonObject& body)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetRoomStateWithKeyJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/state/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/state/",
                        eventType, "/", stateKey))
 {
-    setRequestData(RequestData(toJson(body)));
+    setRequestData({ toJson(body) });
     addExpectedKey("event_id");
 }
diff --git a/lib/csapi/room_upgrades.cpp b/lib/csapi/room_upgrades.cpp
index d4129cfb..b03fb6e8 100644
--- a/lib/csapi/room_upgrades.cpp
+++ b/lib/csapi/room_upgrades.cpp
@@ -8,10 +8,10 @@ using namespace Quotient;
 
 UpgradeRoomJob::UpgradeRoomJob(const QString& roomId, const QString& newVersion)
     : BaseJob(HttpVerb::Post, QStringLiteral("UpgradeRoomJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/upgrade"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/upgrade"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("new_version"), newVersion);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("new_version"), newVersion);
+    setRequestData({ _dataJson });
     addExpectedKey("replacement_room");
 }
diff --git a/lib/csapi/rooms.cpp b/lib/csapi/rooms.cpp
index 5310aa32..563f4fa5 100644
--- a/lib/csapi/rooms.cpp
+++ b/lib/csapi/rooms.cpp
@@ -10,14 +10,14 @@ QUrl GetOneRoomEventJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
                                         const QString& eventId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/event/", eventId));
 }
 
 GetOneRoomEventJob::GetOneRoomEventJob(const QString& roomId,
                                        const QString& eventId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetOneRoomEventJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/event/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/event/",
                        eventId))
 {}
 
@@ -26,7 +26,7 @@ QUrl GetRoomStateWithKeyJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
                                             const QString& stateKey)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/state/", eventType, "/",
                                             stateKey));
 }
@@ -35,20 +35,20 @@ GetRoomStateWithKeyJob::GetRoomStateWithKeyJob(const QString& roomId,
                                                const QString& eventType,
                                                const QString& stateKey)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetRoomStateWithKeyJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/state/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/state/",
                        eventType, "/", stateKey))
 {}
 
 QUrl GetRoomStateJob::makeRequestUrl(QUrl baseUrl, const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/state"));
 }
 
 GetRoomStateJob::GetRoomStateJob(const QString& roomId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetRoomStateJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/state"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/state"))
 {}
 
 auto queryToGetMembersByRoom(const QString& at, const QString& membership,
@@ -68,7 +68,7 @@ QUrl GetMembersByRoomJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
 {
     return BaseJob::makeRequestUrl(
         std::move(baseUrl),
-        makePath("/_matrix/client/r0", "/rooms/", roomId, "/members"),
+        makePath("/_matrix/client/v3", "/rooms/", roomId, "/members"),
         queryToGetMembersByRoom(at, membership, notMembership));
 }
 
@@ -77,7 +77,7 @@ GetMembersByRoomJob::GetMembersByRoomJob(const QString& roomId,
                                          const QString& membership,
                                          const QString& notMembership)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetMembersByRoomJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/members"),
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/members"),
               queryToGetMembersByRoom(at, membership, notMembership))
 {}
 
@@ -85,12 +85,12 @@ QUrl GetJoinedMembersByRoomJob::makeRequestUrl(QUrl baseUrl,
                                                const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/rooms/",
+                                   makePath("/_matrix/client/v3", "/rooms/",
                                             roomId, "/joined_members"));
 }
 
 GetJoinedMembersByRoomJob::GetJoinedMembersByRoomJob(const QString& roomId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetJoinedMembersByRoomJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId,
+              makePath("/_matrix/client/v3", "/rooms/", roomId,
                        "/joined_members"))
 {}
diff --git a/lib/csapi/rooms.h b/lib/csapi/rooms.h
index f0815109..247fb13f 100644
--- a/lib/csapi/rooms.h
+++ b/lib/csapi/rooms.h
@@ -5,7 +5,6 @@
 #pragma once
 
 #include "events/eventloader.h"
-#include "events/roommemberevent.h"
 #include "jobs/basejob.h"
 
 namespace Quotient {
@@ -38,7 +37,7 @@ public:
     // Result properties
 
     /// The full event.
-    EventPtr event() { return fromJson<EventPtr>(jsonData()); }
+    RoomEventPtr event() { return fromJson<RoomEventPtr>(jsonData()); }
 };
 
 /*! \brief Get the state identified by the type and key.
@@ -146,10 +145,7 @@ public:
     // Result properties
 
     /// Get the list of members for this room.
-    EventsArray<RoomMemberEvent> chunk()
-    {
-        return takeFromJson<EventsArray<RoomMemberEvent>>("chunk"_ls);
-    }
+    StateEvents chunk() { return takeFromJson<StateEvents>("chunk"_ls); }
 };
 
 /*! \brief Gets the list of currently joined users and their profile data.
@@ -157,9 +153,8 @@ public:
  * This API returns a map of MXIDs to member info objects for members of the
  * room. The current user must be in the room for it to work, unless it is an
  * Application Service in which case any of the AS's users must be in the room.
- * This API is primarily for Application Services and should be faster to
- * respond than `/members` as it can be implemented more efficiently on the
- * server.
+ * This API is primarily for Application Services and should be faster to respond
+ * than `/members` as it can be implemented more efficiently on the server.
  */
 class QUOTIENT_API GetJoinedMembersByRoomJob : public BaseJob {
 public:
diff --git a/lib/csapi/search.cpp b/lib/csapi/search.cpp
index 295dd1cc..4e2c9e92 100644
--- a/lib/csapi/search.cpp
+++ b/lib/csapi/search.cpp
@@ -16,11 +16,11 @@ auto queryToSearch(const QString& nextBatch)
 SearchJob::SearchJob(const Categories& searchCategories,
                      const QString& nextBatch)
     : BaseJob(HttpVerb::Post, QStringLiteral("SearchJob"),
-              makePath("/_matrix/client/r0", "/search"),
+              makePath("/_matrix/client/v3", "/search"),
               queryToSearch(nextBatch))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("search_categories"), searchCategories);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("search_categories"), searchCategories);
+    setRequestData({ _dataJson });
     addExpectedKey("search_categories");
 }
diff --git a/lib/csapi/space_hierarchy.cpp b/lib/csapi/space_hierarchy.cpp
new file mode 100644
index 00000000..7b5c7eac
--- /dev/null
+++ b/lib/csapi/space_hierarchy.cpp
@@ -0,0 +1,43 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#include "space_hierarchy.h"
+
+using namespace Quotient;
+
+auto queryToGetSpaceHierarchy(Omittable<bool> suggestedOnly,
+                              Omittable<int> limit, Omittable<int> maxDepth,
+                              const QString& from)
+{
+    QUrlQuery _q;
+    addParam<IfNotEmpty>(_q, QStringLiteral("suggested_only"), suggestedOnly);
+    addParam<IfNotEmpty>(_q, QStringLiteral("limit"), limit);
+    addParam<IfNotEmpty>(_q, QStringLiteral("max_depth"), maxDepth);
+    addParam<IfNotEmpty>(_q, QStringLiteral("from"), from);
+    return _q;
+}
+
+QUrl GetSpaceHierarchyJob::makeRequestUrl(QUrl baseUrl, const QString& roomId,
+                                          Omittable<bool> suggestedOnly,
+                                          Omittable<int> limit,
+                                          Omittable<int> maxDepth,
+                                          const QString& from)
+{
+    return BaseJob::makeRequestUrl(
+        std::move(baseUrl),
+        makePath("/_matrix/client/v1", "/rooms/", roomId, "/hierarchy"),
+        queryToGetSpaceHierarchy(suggestedOnly, limit, maxDepth, from));
+}
+
+GetSpaceHierarchyJob::GetSpaceHierarchyJob(const QString& roomId,
+                                           Omittable<bool> suggestedOnly,
+                                           Omittable<int> limit,
+                                           Omittable<int> maxDepth,
+                                           const QString& from)
+    : BaseJob(HttpVerb::Get, QStringLiteral("GetSpaceHierarchyJob"),
+              makePath("/_matrix/client/v1", "/rooms/", roomId, "/hierarchy"),
+              queryToGetSpaceHierarchy(suggestedOnly, limit, maxDepth, from))
+{
+    addExpectedKey("rooms");
+}
diff --git a/lib/csapi/space_hierarchy.h b/lib/csapi/space_hierarchy.h
new file mode 100644
index 00000000..7a421be8
--- /dev/null
+++ b/lib/csapi/space_hierarchy.h
@@ -0,0 +1,152 @@
+/******************************************************************************
+ * THIS FILE IS GENERATED - ANY EDITS WILL BE OVERWRITTEN
+ */
+
+#pragma once
+
+#include "events/eventloader.h"
+#include "jobs/basejob.h"
+
+namespace Quotient {
+
+/*! \brief Retrieve a portion of a space tree.
+ *
+ * Paginates over the space tree in a depth-first manner to locate child rooms
+ * of a given space.
+ *
+ * Where a child room is unknown to the local server, federation is used to fill
+ * in the details. The servers listed in the `via` array should be contacted to
+ * attempt to fill in missing rooms.
+ *
+ * Only [`m.space.child`](#mspacechild) state events of the room are considered.
+ * Invalid child rooms and parent events are not covered by this endpoint.
+ */
+class QUOTIENT_API GetSpaceHierarchyJob : public BaseJob {
+public:
+    // Inner data structures
+
+    /// Paginates over the space tree in a depth-first manner to locate child
+    /// rooms of a given space.
+    ///
+    /// Where a child room is unknown to the local server, federation is used to
+    /// fill in the details. The servers listed in the `via` array should be
+    /// contacted to attempt to fill in missing rooms.
+    ///
+    /// Only [`m.space.child`](#mspacechild) state events of the room are
+    /// considered. Invalid child rooms and parent events are not covered by
+    /// this endpoint.
+    struct ChildRoomsChunk {
+        /// The canonical alias of the room, if any.
+        QString canonicalAlias;
+        /// The name of the room, if any.
+        QString name;
+        /// The number of members joined to the room.
+        int numJoinedMembers;
+        /// The ID of the room.
+        QString roomId;
+        /// The topic of the room, if any.
+        QString topic;
+        /// Whether the room may be viewed by guest users without joining.
+        bool worldReadable;
+        /// Whether guest users may join the room and participate in it.
+        /// If they can, they will be subject to ordinary power level
+        /// rules like any other user.
+        bool guestCanJoin;
+        /// The URL for the room's avatar, if one is set.
+        QUrl avatarUrl;
+        /// The room's join rule. When not present, the room is assumed to
+        /// be `public`.
+        QString joinRule;
+        /// The `type` of room (from
+        /// [`m.room.create`](/client-server-api/#mroomcreate)), if any.
+        QString roomType;
+        /// The [`m.space.child`](#mspacechild) events of the space-room,
+        /// represented as [Stripped State Events](#stripped-state) with an
+        /// added `origin_server_ts` key.
+        ///
+        /// If the room is not a space-room, this should be empty.
+        StateEvents childrenState;
+    };
+
+    // Construction/destruction
+
+    /*! \brief Retrieve a portion of a space tree.
+     *
+     * \param roomId
+     *   The room ID of the space to get a hierarchy for.
+     *
+     * \param suggestedOnly
+     *   Optional (default `false`) flag to indicate whether or not the server
+     * should only consider suggested rooms. Suggested rooms are annotated in
+     * their [`m.space.child`](#mspacechild) event contents.
+     *
+     * \param limit
+     *   Optional limit for the maximum number of rooms to include per response.
+     * Must be an integer greater than zero.
+     *
+     *   Servers should apply a default value, and impose a maximum value to
+     * avoid resource exhaustion.
+     *
+     * \param maxDepth
+     *   Optional limit for how far to go into the space. Must be a non-negative
+     * integer.
+     *
+     *   When reached, no further child rooms will be returned.
+     *
+     *   Servers should apply a default value, and impose a maximum value to
+     * avoid resource exhaustion.
+     *
+     * \param from
+     *   A pagination token from a previous result. If specified, `max_depth`
+     * and `suggested_only` cannot be changed from the first request.
+     */
+    explicit GetSpaceHierarchyJob(const QString& roomId,
+                                  Omittable<bool> suggestedOnly = none,
+                                  Omittable<int> limit = none,
+                                  Omittable<int> maxDepth = none,
+                                  const QString& from = {});
+
+    /*! \brief Construct a URL without creating a full-fledged job object
+     *
+     * This function can be used when a URL for GetSpaceHierarchyJob
+     * is necessary but the job itself isn't.
+     */
+    static QUrl makeRequestUrl(QUrl baseUrl, const QString& roomId,
+                               Omittable<bool> suggestedOnly = none,
+                               Omittable<int> limit = none,
+                               Omittable<int> maxDepth = none,
+                               const QString& from = {});
+
+    // Result properties
+
+    /// The rooms for the current page, with the current filters.
+    std::vector<ChildRoomsChunk> rooms()
+    {
+        return takeFromJson<std::vector<ChildRoomsChunk>>("rooms"_ls);
+    }
+
+    /// A token to supply to `from` to keep paginating the responses. Not
+    /// present when there are no further results.
+    QString nextBatch() const { return loadFromJson<QString>("next_batch"_ls); }
+};
+
+template <>
+struct JsonObjectConverter<GetSpaceHierarchyJob::ChildRoomsChunk> {
+    static void fillFrom(const QJsonObject& jo,
+                         GetSpaceHierarchyJob::ChildRoomsChunk& result)
+    {
+        fromJson(jo.value("canonical_alias"_ls), result.canonicalAlias);
+        fromJson(jo.value("name"_ls), result.name);
+        fromJson(jo.value("num_joined_members"_ls), result.numJoinedMembers);
+        fromJson(jo.value("room_id"_ls), result.roomId);
+        fromJson(jo.value("topic"_ls), result.topic);
+        fromJson(jo.value("world_readable"_ls), result.worldReadable);
+        fromJson(jo.value("guest_can_join"_ls), result.guestCanJoin);
+        fromJson(jo.value("avatar_url"_ls), result.avatarUrl);
+        fromJson(jo.value("join_rule"_ls), result.joinRule);
+        fromJson(jo.value("room_type"_ls), result.roomType);
+        fromJson(jo.value("children_state"_ls), result.childrenState);
+    }
+};
+
+} // namespace Quotient
diff --git a/lib/csapi/sso_login_redirect.cpp b/lib/csapi/sso_login_redirect.cpp
index 871d6ff6..71f8147c 100644
--- a/lib/csapi/sso_login_redirect.cpp
+++ b/lib/csapi/sso_login_redirect.cpp
@@ -16,14 +16,14 @@ auto queryToRedirectToSSO(const QString& redirectUrl)
 QUrl RedirectToSSOJob::makeRequestUrl(QUrl baseUrl, const QString& redirectUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/login/sso/redirect"),
                                    queryToRedirectToSSO(redirectUrl));
 }
 
 RedirectToSSOJob::RedirectToSSOJob(const QString& redirectUrl)
     : BaseJob(HttpVerb::Get, QStringLiteral("RedirectToSSOJob"),
-              makePath("/_matrix/client/r0", "/login/sso/redirect"),
+              makePath("/_matrix/client/v3", "/login/sso/redirect"),
               queryToRedirectToSSO(redirectUrl), {}, false)
 {}
 
@@ -38,7 +38,7 @@ QUrl RedirectToIdPJob::makeRequestUrl(QUrl baseUrl, const QString& idpId,
                                       const QString& redirectUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/login/sso/redirect/", idpId),
                                    queryToRedirectToIdP(redirectUrl));
 }
@@ -46,6 +46,6 @@ QUrl RedirectToIdPJob::makeRequestUrl(QUrl baseUrl, const QString& idpId,
 RedirectToIdPJob::RedirectToIdPJob(const QString& idpId,
                                    const QString& redirectUrl)
     : BaseJob(HttpVerb::Get, QStringLiteral("RedirectToIdPJob"),
-              makePath("/_matrix/client/r0", "/login/sso/redirect/", idpId),
+              makePath("/_matrix/client/v3", "/login/sso/redirect/", idpId),
               queryToRedirectToIdP(redirectUrl), {}, false)
 {}
diff --git a/lib/csapi/tags.cpp b/lib/csapi/tags.cpp
index f717de6e..2c85842d 100644
--- a/lib/csapi/tags.cpp
+++ b/lib/csapi/tags.cpp
@@ -10,13 +10,13 @@ QUrl GetRoomTagsJob::makeRequestUrl(QUrl baseUrl, const QString& userId,
                                     const QString& roomId)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/user/",
+                                   makePath("/_matrix/client/v3", "/user/",
                                             userId, "/rooms/", roomId, "/tags"));
 }
 
 GetRoomTagsJob::GetRoomTagsJob(const QString& userId, const QString& roomId)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetRoomTagsJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/rooms/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/rooms/",
                        roomId, "/tags"))
 {}
 
@@ -24,20 +24,20 @@ SetRoomTagJob::SetRoomTagJob(const QString& userId, const QString& roomId,
                              const QString& tag, Omittable<float> order,
                              const QVariantHash& additionalProperties)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetRoomTagJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/rooms/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/rooms/",
                        roomId, "/tags/", tag))
 {
-    QJsonObject _data;
-    fillJson(_data, additionalProperties);
-    addParam<IfNotEmpty>(_data, QStringLiteral("order"), order);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    fillJson(_dataJson, additionalProperties);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("order"), order);
+    setRequestData({ _dataJson });
 }
 
 QUrl DeleteRoomTagJob::makeRequestUrl(QUrl baseUrl, const QString& userId,
                                       const QString& roomId, const QString& tag)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0", "/user/",
+                                   makePath("/_matrix/client/v3", "/user/",
                                             userId, "/rooms/", roomId, "/tags/",
                                             tag));
 }
@@ -45,6 +45,6 @@ QUrl DeleteRoomTagJob::makeRequestUrl(QUrl baseUrl, const QString& userId,
 DeleteRoomTagJob::DeleteRoomTagJob(const QString& userId, const QString& roomId,
                                    const QString& tag)
     : BaseJob(HttpVerb::Delete, QStringLiteral("DeleteRoomTagJob"),
-              makePath("/_matrix/client/r0", "/user/", userId, "/rooms/",
+              makePath("/_matrix/client/v3", "/user/", userId, "/rooms/",
                        roomId, "/tags/", tag))
 {}
diff --git a/lib/csapi/third_party_lookup.cpp b/lib/csapi/third_party_lookup.cpp
index 4c930668..1e5870ce 100644
--- a/lib/csapi/third_party_lookup.cpp
+++ b/lib/csapi/third_party_lookup.cpp
@@ -9,26 +9,26 @@ using namespace Quotient;
 QUrl GetProtocolsJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/thirdparty/protocols"));
 }
 
 GetProtocolsJob::GetProtocolsJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetProtocolsJob"),
-              makePath("/_matrix/client/r0", "/thirdparty/protocols"))
+              makePath("/_matrix/client/v3", "/thirdparty/protocols"))
 {}
 
 QUrl GetProtocolMetadataJob::makeRequestUrl(QUrl baseUrl,
                                             const QString& protocol)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/thirdparty/protocol/", protocol));
 }
 
 GetProtocolMetadataJob::GetProtocolMetadataJob(const QString& protocol)
     : BaseJob(HttpVerb::Get, QStringLiteral("GetProtocolMetadataJob"),
-              makePath("/_matrix/client/r0", "/thirdparty/protocol/", protocol))
+              makePath("/_matrix/client/v3", "/thirdparty/protocol/", protocol))
 {}
 
 auto queryToQueryLocationByProtocol(const QString& searchFields)
@@ -43,7 +43,7 @@ QUrl QueryLocationByProtocolJob::makeRequestUrl(QUrl baseUrl,
                                                 const QString& searchFields)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/thirdparty/location/", protocol),
                                    queryToQueryLocationByProtocol(searchFields));
 }
@@ -51,7 +51,7 @@ QUrl QueryLocationByProtocolJob::makeRequestUrl(QUrl baseUrl,
 QueryLocationByProtocolJob::QueryLocationByProtocolJob(
     const QString& protocol, const QString& searchFields)
     : BaseJob(HttpVerb::Get, QStringLiteral("QueryLocationByProtocolJob"),
-              makePath("/_matrix/client/r0", "/thirdparty/location/", protocol),
+              makePath("/_matrix/client/v3", "/thirdparty/location/", protocol),
               queryToQueryLocationByProtocol(searchFields))
 {}
 
@@ -67,7 +67,7 @@ QUrl QueryUserByProtocolJob::makeRequestUrl(QUrl baseUrl,
                                             const QString& fields)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/thirdparty/user/", protocol),
                                    queryToQueryUserByProtocol(fields));
 }
@@ -75,7 +75,7 @@ QUrl QueryUserByProtocolJob::makeRequestUrl(QUrl baseUrl,
 QueryUserByProtocolJob::QueryUserByProtocolJob(const QString& protocol,
                                                const QString& fields)
     : BaseJob(HttpVerb::Get, QStringLiteral("QueryUserByProtocolJob"),
-              makePath("/_matrix/client/r0", "/thirdparty/user/", protocol),
+              makePath("/_matrix/client/v3", "/thirdparty/user/", protocol),
               queryToQueryUserByProtocol(fields))
 {}
 
@@ -89,14 +89,14 @@ auto queryToQueryLocationByAlias(const QString& alias)
 QUrl QueryLocationByAliasJob::makeRequestUrl(QUrl baseUrl, const QString& alias)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/thirdparty/location"),
                                    queryToQueryLocationByAlias(alias));
 }
 
 QueryLocationByAliasJob::QueryLocationByAliasJob(const QString& alias)
     : BaseJob(HttpVerb::Get, QStringLiteral("QueryLocationByAliasJob"),
-              makePath("/_matrix/client/r0", "/thirdparty/location"),
+              makePath("/_matrix/client/v3", "/thirdparty/location"),
               queryToQueryLocationByAlias(alias))
 {}
 
@@ -110,13 +110,13 @@ auto queryToQueryUserByID(const QString& userid)
 QUrl QueryUserByIDJob::makeRequestUrl(QUrl baseUrl, const QString& userid)
 {
     return BaseJob::makeRequestUrl(std::move(baseUrl),
-                                   makePath("/_matrix/client/r0",
+                                   makePath("/_matrix/client/v3",
                                             "/thirdparty/user"),
                                    queryToQueryUserByID(userid));
 }
 
 QueryUserByIDJob::QueryUserByIDJob(const QString& userid)
     : BaseJob(HttpVerb::Get, QStringLiteral("QueryUserByIDJob"),
-              makePath("/_matrix/client/r0", "/thirdparty/user"),
+              makePath("/_matrix/client/v3", "/thirdparty/user"),
               queryToQueryUserByID(userid))
 {}
diff --git a/lib/csapi/third_party_membership.cpp b/lib/csapi/third_party_membership.cpp
index 59275e41..3ca986c7 100644
--- a/lib/csapi/third_party_membership.cpp
+++ b/lib/csapi/third_party_membership.cpp
@@ -10,12 +10,12 @@ InviteBy3PIDJob::InviteBy3PIDJob(const QString& roomId, const QString& idServer,
                                  const QString& idAccessToken,
                                  const QString& medium, const QString& address)
     : BaseJob(HttpVerb::Post, QStringLiteral("InviteBy3PIDJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/invite"))
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/invite"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("id_server"), idServer);
-    addParam<>(_data, QStringLiteral("id_access_token"), idAccessToken);
-    addParam<>(_data, QStringLiteral("medium"), medium);
-    addParam<>(_data, QStringLiteral("address"), address);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("id_server"), idServer);
+    addParam<>(_dataJson, QStringLiteral("id_access_token"), idAccessToken);
+    addParam<>(_dataJson, QStringLiteral("medium"), medium);
+    addParam<>(_dataJson, QStringLiteral("address"), address);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/third_party_membership.h b/lib/csapi/third_party_membership.h
index 1edb969e..1129a9a8 100644
--- a/lib/csapi/third_party_membership.h
+++ b/lib/csapi/third_party_membership.h
@@ -16,7 +16,7 @@ namespace Quotient {
  * The homeserver uses an identity server to perform the mapping from
  * third party identifier to a Matrix identifier. The other is documented in
  * the* [joining rooms
- * section](/client-server-api/#post_matrixclientr0roomsroomidinvite).
+ * section](/client-server-api/#post_matrixclientv3roomsroomidinvite).
  *
  * This API invites a user to participate in a particular room.
  * They do not start participating in the room until they actually join the
diff --git a/lib/csapi/to_device.cpp b/lib/csapi/to_device.cpp
index 628e8314..e10fac69 100644
--- a/lib/csapi/to_device.cpp
+++ b/lib/csapi/to_device.cpp
@@ -10,10 +10,10 @@ SendToDeviceJob::SendToDeviceJob(
     const QString& eventType, const QString& txnId,
     const QHash<QString, QHash<QString, QJsonObject>>& messages)
     : BaseJob(HttpVerb::Put, QStringLiteral("SendToDeviceJob"),
-              makePath("/_matrix/client/r0", "/sendToDevice/", eventType, "/",
+              makePath("/_matrix/client/v3", "/sendToDevice/", eventType, "/",
                        txnId))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("messages"), messages);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("messages"), messages);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/typing.cpp b/lib/csapi/typing.cpp
index c9673118..21bd45ae 100644
--- a/lib/csapi/typing.cpp
+++ b/lib/csapi/typing.cpp
@@ -9,11 +9,11 @@ using namespace Quotient;
 SetTypingJob::SetTypingJob(const QString& userId, const QString& roomId,
                            bool typing, Omittable<int> timeout)
     : BaseJob(HttpVerb::Put, QStringLiteral("SetTypingJob"),
-              makePath("/_matrix/client/r0", "/rooms/", roomId, "/typing/",
+              makePath("/_matrix/client/v3", "/rooms/", roomId, "/typing/",
                        userId))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("typing"), typing);
-    addParam<IfNotEmpty>(_data, QStringLiteral("timeout"), timeout);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("typing"), typing);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("timeout"), timeout);
+    setRequestData({ _dataJson });
 }
diff --git a/lib/csapi/users.cpp b/lib/csapi/users.cpp
index 48b727f0..c65280ee 100644
--- a/lib/csapi/users.cpp
+++ b/lib/csapi/users.cpp
@@ -9,12 +9,12 @@ using namespace Quotient;
 SearchUserDirectoryJob::SearchUserDirectoryJob(const QString& searchTerm,
                                                Omittable<int> limit)
     : BaseJob(HttpVerb::Post, QStringLiteral("SearchUserDirectoryJob"),
-              makePath("/_matrix/client/r0", "/user_directory/search"))
+              makePath("/_matrix/client/v3", "/user_directory/search"))
 {
-    QJsonObject _data;
-    addParam<>(_data, QStringLiteral("search_term"), searchTerm);
-    addParam<IfNotEmpty>(_data, QStringLiteral("limit"), limit);
-    setRequestData(std::move(_data));
+    QJsonObject _dataJson;
+    addParam<>(_dataJson, QStringLiteral("search_term"), searchTerm);
+    addParam<IfNotEmpty>(_dataJson, QStringLiteral("limit"), limit);
+    setRequestData({ _dataJson });
     addExpectedKey("results");
     addExpectedKey("limited");
 }
diff --git a/lib/csapi/versions.h b/lib/csapi/versions.h
index 4445dbd2..9f799cb0 100644
--- a/lib/csapi/versions.h
+++ b/lib/csapi/versions.h
@@ -12,11 +12,9 @@ namespace Quotient {
  *
  * Gets the versions of the specification supported by the server.
  *
- * Values will take the form `rX.Y.Z`.
- *
- * Only the latest `Z` value will be reported for each supported `X.Y` value.
- * i.e. if the server implements `r0.0.0`, `r0.0.1`, and `r1.2.0`, it will
- * report `r0.0.1` and `r1.2.0`.
+ * Values will take the form `vX.Y` or `rX.Y.Z` in historical cases. See
+ * [the Specification Versioning](../#specification-versions) for more
+ * information.
  *
  * The server may additionally advertise experimental features it supports
  * through `unstable_features`. These features should be namespaced and
diff --git a/lib/csapi/voip.cpp b/lib/csapi/voip.cpp
index c748ad94..1e1f2441 100644
--- a/lib/csapi/voip.cpp
+++ b/lib/csapi/voip.cpp
@@ -9,10 +9,10 @@ using namespace Quotient;
 QUrl GetTurnServerJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/voip/turnServer"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/voip/turnServer"));
 }
 
 GetTurnServerJob::GetTurnServerJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetTurnServerJob"),
-              makePath("/_matrix/client/r0", "/voip/turnServer"))
+              makePath("/_matrix/client/v3", "/voip/turnServer"))
 {}
diff --git a/lib/csapi/whoami.cpp b/lib/csapi/whoami.cpp
index ed8a9817..af0c5d31 100644
--- a/lib/csapi/whoami.cpp
+++ b/lib/csapi/whoami.cpp
@@ -9,12 +9,12 @@ using namespace Quotient;
 QUrl GetTokenOwnerJob::makeRequestUrl(QUrl baseUrl)
 {
     return BaseJob::makeRequestUrl(
-        std::move(baseUrl), makePath("/_matrix/client/r0", "/account/whoami"));
+        std::move(baseUrl), makePath("/_matrix/client/v3", "/account/whoami"));
 }
 
 GetTokenOwnerJob::GetTokenOwnerJob()
     : BaseJob(HttpVerb::Get, QStringLiteral("GetTokenOwnerJob"),
-              makePath("/_matrix/client/r0", "/account/whoami"))
+              makePath("/_matrix/client/v3", "/account/whoami"))
 {
     addExpectedKey("user_id");
 }
diff --git a/lib/csapi/whoami.h b/lib/csapi/whoami.h
index fba099f6..3451dbc3 100644
--- a/lib/csapi/whoami.h
+++ b/lib/csapi/whoami.h
@@ -41,6 +41,14 @@ public:
     /// of application services) then this field can be omitted.
     /// Otherwise this is required.
     QString deviceId() const { return loadFromJson<QString>("device_id"_ls); }
+
+    /// When `true`, the user is a [Guest User](#guest-access). When
+    /// not present or `false`, the user is presumed to be a non-guest
+    /// user.
+    Omittable<bool> isGuest() const
+    {
+        return loadFromJson<Omittable<bool>>("is_guest"_ls);
+    }
 };
 
 } // namespace Quotient
diff --git a/lib/database.cpp b/lib/database.cpp
index a85d96bb..79793b9d 100644
--- a/lib/database.cpp
+++ b/lib/database.cpp
@@ -14,9 +14,7 @@
 #include "e2ee/e2ee.h"
 #include "e2ee/qolmsession.h"
 #include "e2ee/qolminboundsession.h"
-#include "connection.h"
-#include "user.h"
-#include "room.h"
+#include "e2ee/qolmoutboundsession.h"
 
 using namespace Quotient;
 Database::Database(const QString& matrixId, const QString& deviceId, QObject* parent)
@@ -31,11 +29,11 @@ Database::Database(const QString& matrixId, const QString& deviceId, QObject* pa
     database().open();
 
     switch(version()) {
-        case 0: migrateTo1();
-        case 1: migrateTo2();
-        case 2: migrateTo3();
-        case 3: migrateTo4();
-        case 4: migrateTo5();
+    case 0: migrateTo1(); [[fallthrough]];
+    case 1: migrateTo2(); [[fallthrough]];
+    case 2: migrateTo3(); [[fallthrough]];
+    case 3: migrateTo4(); [[fallthrough]];
+    case 4: migrateTo5();
     }
 }
 
@@ -43,7 +41,7 @@ int Database::version()
 {
     auto query = execute(QStringLiteral("PRAGMA user_version;"));
     if (query.next()) {
-        bool ok;
+        bool ok = false;
         int value = query.value(0).toInt(&ok);
         qCDebug(DATABASE) << "Database version" << value;
         if (ok)
@@ -212,12 +210,14 @@ UnorderedMap<QString, std::vector<QOlmSessionPtr>> Database::loadOlmSessions(con
     commit();
     UnorderedMap<QString, std::vector<QOlmSessionPtr>> sessions;
     while (query.next()) {
-        auto session = QOlmSession::unpickle(query.value("pickle").toByteArray(), picklingMode);
-        if (std::holds_alternative<QOlmError>(session)) {
-            qCWarning(E2EE) << "Failed to unpickle olm session";
-            continue;
-        }
-        sessions[query.value("senderKey").toString()].push_back(std::move(std::get<QOlmSessionPtr>(session)));
+        if (auto expectedSession =
+                QOlmSession::unpickle(query.value("pickle").toByteArray(),
+                                      picklingMode)) {
+            sessions[query.value("senderKey").toString()].emplace_back(
+                std::move(*expectedSession));
+        } else
+            qCWarning(E2EE)
+                << "Failed to unpickle olm session:" << expectedSession.error();
     }
     return sessions;
 }
@@ -231,15 +231,15 @@ UnorderedMap<QString, QOlmInboundGroupSessionPtr> Database::loadMegolmSessions(c
     commit();
     UnorderedMap<QString, QOlmInboundGroupSessionPtr> sessions;
     while (query.next()) {
-        auto session = QOlmInboundGroupSession::unpickle(query.value("pickle").toByteArray(), picklingMode);
-        if (std::holds_alternative<QOlmError>(session)) {
-            qCWarning(E2EE) << "Failed to unpickle megolm session";
-            continue;
-        }
-
-        sessions[query.value("sessionId").toString()] = std::move(std::get<QOlmInboundGroupSessionPtr>(session));
-        sessions[query.value("sessionId").toString()]->setOlmSessionId(query.value("olmSessionId").toString());
-        sessions[query.value("sessionId").toString()]->setSenderId(query.value("senderId").toString());
+        if (auto expectedSession = QOlmInboundGroupSession::unpickle(
+                query.value("pickle").toByteArray(), picklingMode)) {
+            auto& sessionPtr = sessions[query.value("sessionId").toString()] =
+                std::move(*expectedSession);
+            sessionPtr->setOlmSessionId(query.value("olmSessionId").toString());
+            sessionPtr->setSenderId(query.value("senderId").toString());
+        } else
+            qCWarning(E2EE) << "Failed to unpickle megolm session:"
+                            << expectedSession.error();
     }
     return sessions;
 }
@@ -319,20 +319,22 @@ void Database::setOlmSessionLastReceived(const QString& sessionId, const QDateTi
     commit();
 }
 
-void Database::saveCurrentOutboundMegolmSession(const QString& roomId, const PicklingMode& picklingMode, const QOlmOutboundGroupSessionPtr& session)
+void Database::saveCurrentOutboundMegolmSession(
+    const QString& roomId, const PicklingMode& picklingMode,
+    const QOlmOutboundGroupSession& session)
 {
-    const auto pickle = session->pickle(picklingMode);
-    if (std::holds_alternative<QByteArray>(pickle)) {
+    const auto pickle = session.pickle(picklingMode);
+    if (pickle) {
         auto deleteQuery = prepareQuery(QStringLiteral("DELETE FROM outbound_megolm_sessions WHERE roomId=:roomId AND sessionId=:sessionId;"));
         deleteQuery.bindValue(":roomId", roomId);
-        deleteQuery.bindValue(":sessionId", session->sessionId());
+        deleteQuery.bindValue(":sessionId", session.sessionId());
 
         auto insertQuery = prepareQuery(QStringLiteral("INSERT INTO outbound_megolm_sessions(roomId, sessionId, pickle, creationTime, messageCount) VALUES(:roomId, :sessionId, :pickle, :creationTime, :messageCount);"));
         insertQuery.bindValue(":roomId", roomId);
-        insertQuery.bindValue(":sessionId", session->sessionId());
-        insertQuery.bindValue(":pickle", std::get<QByteArray>(pickle));
-        insertQuery.bindValue(":creationTime", session->creationTime());
-        insertQuery.bindValue(":messageCount", session->messageCount());
+        insertQuery.bindValue(":sessionId", session.sessionId());
+        insertQuery.bindValue(":pickle", pickle.value());
+        insertQuery.bindValue(":creationTime", session.creationTime());
+        insertQuery.bindValue(":messageCount", session.messageCount());
 
         transaction();
         execute(deleteQuery);
@@ -348,8 +350,8 @@ QOlmOutboundGroupSessionPtr Database::loadCurrentOutboundMegolmSession(const QSt
     execute(query);
     if (query.next()) {
         auto sessionResult = QOlmOutboundGroupSession::unpickle(query.value("pickle").toByteArray(), picklingMode);
-        if (std::holds_alternative<QOlmOutboundGroupSessionPtr>(sessionResult)) {
-            auto session = std::move(std::get<QOlmOutboundGroupSessionPtr>(sessionResult));
+        if (sessionResult) {
+            auto session = std::move(*sessionResult);
             session->setCreationTime(query.value("creationTime").toDateTime());
             session->setMessageCount(query.value("messageCount").toInt());
             return session;
@@ -358,41 +360,35 @@ QOlmOutboundGroupSessionPtr Database::loadCurrentOutboundMegolmSession(const QSt
     return nullptr;
 }
 
-void Database::setDevicesReceivedKey(const QString& roomId, QHash<User *, QStringList> devices, const QString& sessionId, int index)
+void Database::setDevicesReceivedKey(const QString& roomId, const QVector<std::tuple<QString, QString, QString>>& devices, const QString& sessionId, int index)
 {
-    auto connection = dynamic_cast<Connection *>(parent());
     transaction();
-    for (const auto& user : devices.keys()) {
-        for (const auto& device : devices[user]) {
-            auto query = prepareQuery(QStringLiteral("INSERT INTO sent_megolm_sessions(roomId, userId, deviceId, identityKey, sessionId, i) VALUES(:roomId, :userId, :deviceId, :identityKey, :sessionId, :i);"));
-            query.bindValue(":roomId", roomId);
-            query.bindValue(":userId", user->id());
-            query.bindValue(":deviceId", device);
-            query.bindValue(":identityKey", connection->curveKeyForUserDevice(user->id(), device));
-            query.bindValue(":sessionId", sessionId);
-            query.bindValue(":i", index);
-            execute(query);
-        }
+    for (const auto& [user, device, curveKey] : devices) {
+        auto query = prepareQuery(QStringLiteral("INSERT INTO sent_megolm_sessions(roomId, userId, deviceId, identityKey, sessionId, i) VALUES(:roomId, :userId, :deviceId, :identityKey, :sessionId, :i);"));
+        query.bindValue(":roomId", roomId);
+        query.bindValue(":userId", user);
+        query.bindValue(":deviceId", device);
+        query.bindValue(":identityKey", curveKey);
+        query.bindValue(":sessionId", sessionId);
+        query.bindValue(":i", index);
+        execute(query);
     }
     commit();
 }
 
-QHash<QString, QStringList> Database::devicesWithoutKey(Room* room, const QString &sessionId)
+QMultiHash<QString, QString> Database::devicesWithoutKey(
+    const QString& roomId, QMultiHash<QString, QString> devices,
+    const QString& sessionId)
 {
-    auto connection = dynamic_cast<Connection *>(parent());
-    QHash<QString, QStringList> devices;
-    for (const auto& user : room->users()) {
-        devices[user->id()] = connection->devicesForUser(user);
-    }
-
     auto query = prepareQuery(QStringLiteral("SELECT userId, deviceId FROM sent_megolm_sessions WHERE roomId=:roomId AND sessionId=:sessionId"));
-    query.bindValue(":roomId", room->id());
+    query.bindValue(":roomId", roomId);
     query.bindValue(":sessionId", sessionId);
     transaction();
     execute(query);
     commit();
     while (query.next()) {
-        devices[query.value("userId").toString()].removeAll(query.value("deviceId").toString());
+        devices.remove(query.value("userId").toString(),
+                       query.value("deviceId").toString());
     }
     return devices;
 }
diff --git a/lib/database.h b/lib/database.h
index afc41e42..8a133f8e 100644
--- a/lib/database.h
+++ b/lib/database.h
@@ -11,11 +11,7 @@
 
 #include "e2ee/e2ee.h"
 
-#include "e2ee/qolmoutboundsession.h"
-
 namespace Quotient {
-class User;
-class Room;
 
 class QUOTIENT_API Database : public QObject
 {
@@ -34,21 +30,41 @@ public:
     QByteArray accountPickle();
     void setAccountPickle(const QByteArray &pickle);
     void clear();
-    void saveOlmSession(const QString& senderKey, const QString& sessionId, const QByteArray& pickle, const QDateTime& timestamp);
-    UnorderedMap<QString, std::vector<QOlmSessionPtr>> loadOlmSessions(const PicklingMode& picklingMode);
-    UnorderedMap<QString, QOlmInboundGroupSessionPtr> loadMegolmSessions(const QString& roomId, const PicklingMode& picklingMode);
-    void saveMegolmSession(const QString& roomId, const QString& sessionId, const QByteArray& pickle, const QString& senderId, const QString& olmSessionId);
-    void addGroupSessionIndexRecord(const QString& roomId, const QString& sessionId, uint32_t index, const QString& eventId, qint64 ts);
-    std::pair<QString, qint64> groupSessionIndexRecord(const QString& roomId, const QString& sessionId, qint64 index);
+    void saveOlmSession(const QString& senderKey, const QString& sessionId,
+                        const QByteArray& pickle, const QDateTime& timestamp);
+    UnorderedMap<QString, std::vector<QOlmSessionPtr>> loadOlmSessions(
+        const PicklingMode& picklingMode);
+    UnorderedMap<QString, QOlmInboundGroupSessionPtr> loadMegolmSessions(
+        const QString& roomId, const PicklingMode& picklingMode);
+    void saveMegolmSession(const QString& roomId, const QString& sessionId,
+                           const QByteArray& pickle, const QString& senderId,
+                           const QString& olmSessionId);
+    void addGroupSessionIndexRecord(const QString& roomId,
+                                    const QString& sessionId, uint32_t index,
+                                    const QString& eventId, qint64 ts);
+    std::pair<QString, qint64> groupSessionIndexRecord(const QString& roomId,
+                                                       const QString& sessionId,
+                                                       qint64 index);
     void clearRoomData(const QString& roomId);
-    void setOlmSessionLastReceived(const QString& sessionId, const QDateTime& timestamp);
-    QOlmOutboundGroupSessionPtr loadCurrentOutboundMegolmSession(const QString& roomId, const PicklingMode& picklingMode);
-    void saveCurrentOutboundMegolmSession(const QString& roomId, const PicklingMode& picklingMode, const QOlmOutboundGroupSessionPtr& data);
-    void updateOlmSession(const QString& senderKey, const QString& sessionId, const QByteArray& pickle);
+    void setOlmSessionLastReceived(const QString& sessionId,
+                                   const QDateTime& timestamp);
+    QOlmOutboundGroupSessionPtr loadCurrentOutboundMegolmSession(
+        const QString& roomId, const PicklingMode& picklingMode);
+    void saveCurrentOutboundMegolmSession(
+        const QString& roomId, const PicklingMode& picklingMode,
+        const QOlmOutboundGroupSession& session);
+    void updateOlmSession(const QString& senderKey, const QString& sessionId,
+                          const QByteArray& pickle);
 
-    // Returns a map User -> [Device] that have not received key yet
-    QHash<QString, QStringList> devicesWithoutKey(Room* room, const QString &sessionId);
-    void setDevicesReceivedKey(const QString& roomId, QHash<User *, QStringList> devices, const QString& sessionId, int index);
+    // Returns a map UserId -> [DeviceId] that have not received key yet
+    QMultiHash<QString, QString> devicesWithoutKey(
+        const QString& roomId, QMultiHash<QString, QString> devices,
+        const QString& sessionId);
+    // 'devices' contains tuples {userId, deviceId, curveKey}
+    void setDevicesReceivedKey(
+        const QString& roomId,
+        const QVector<std::tuple<QString, QString, QString>>& devices,
+        const QString& sessionId, int index);
 
     bool isSessionVerified(const QString& edKey);
     void setSessionVerified(const QString& edKeyId);
@@ -62,4 +78,4 @@ private:
 
     QString m_matrixId;
 };
-}
+} // namespace Quotient
diff --git a/lib/e2ee/e2ee.h b/lib/e2ee/e2ee.h
index 268cb525..0772b70a 100644
--- a/lib/e2ee/e2ee.h
+++ b/lib/e2ee/e2ee.h
@@ -6,9 +6,13 @@
 #pragma once
 
 #include "converters.h"
-#include "quotient_common.h"
+#include "expected.h"
+#include "qolmerrors.h"
 
 #include <QtCore/QMetaType>
+#include <QtCore/QStringBuilder>
+
+#include <array>
 #include <variant>
 
 namespace Quotient {
@@ -33,10 +37,11 @@ constexpr auto SignedCurve25519Key = "signed_curve25519"_ls;
 constexpr auto OlmV1Curve25519AesSha2AlgoKey = "m.olm.v1.curve25519-aes-sha2"_ls;
 constexpr auto MegolmV1AesSha2AlgoKey = "m.megolm.v1.aes-sha2"_ls;
 
+constexpr std::array SupportedAlgorithms { OlmV1Curve25519AesSha2AlgoKey,
+                                           MegolmV1AesSha2AlgoKey };
+
 inline bool isSupportedAlgorithm(const QString& algorithm)
 {
-    static constexpr auto SupportedAlgorithms =
-        make_array(OlmV1Curve25519AesSha2AlgoKey, MegolmV1AesSha2AlgoKey);
     return std::find(SupportedAlgorithms.cbegin(), SupportedAlgorithms.cend(),
                      algorithm)
            != SupportedAlgorithms.cend();
@@ -55,6 +60,12 @@ using QOlmSessionPtr = std::unique_ptr<QOlmSession>;
 class QOlmInboundGroupSession;
 using QOlmInboundGroupSessionPtr = std::unique_ptr<QOlmInboundGroupSession>;
 
+class QOlmOutboundGroupSession;
+using QOlmOutboundGroupSessionPtr = std::unique_ptr<QOlmOutboundGroupSession>;
+
+template <typename T>
+using QOlmExpected = Expected<T, QOlmError>;
+
 struct IdentityKeys
 {
     QByteArray curve25519;
@@ -62,45 +73,66 @@ struct IdentityKeys
 };
 
 //! Struct representing the one-time keys.
-struct QUOTIENT_API OneTimeKeys
+struct UnsignedOneTimeKeys
 {
     QHash<QString, QHash<QString, QString>> keys;
 
     //! Get the HashMap containing the curve25519 one-time keys.
-    QHash<QString, QString> curve25519() const;
-
-    //! Get a reference to the hashmap corresponding to given key type.
-//    std::optional<QHash<QString, QString>> get(QString keyType) const;
+    QHash<QString, QString> curve25519() const { return keys[Curve25519Key]; }
 };
 
-//! Struct representing the signed one-time keys.
-class SignedOneTimeKey
-{
+class SignedOneTimeKey {
 public:
-    //! Required. The unpadded Base64-encoded 32-byte Curve25519 public key.
-    QString key;
+    explicit SignedOneTimeKey(const QString& unsignedKey, const QString& userId,
+                              const QString& deviceId,
+                              const QByteArray& signature)
+        : payload { { "key"_ls, unsignedKey },
+                    { "signatures"_ls,
+                      QJsonObject {
+                          { userId, QJsonObject { { "ed25519:"_ls % deviceId,
+                                                    QString(signature) } } } } } }
+    {}
+    explicit SignedOneTimeKey(const QJsonObject& jo = {})
+        : payload(jo)
+    {}
 
-    //! Required. Signatures of the key object.
-    //! The signature is calculated using the process described at Signing JSON.
-    QHash<QString, QHash<QString, QString>> signatures;
-};
+    //! Unpadded Base64-encoded 32-byte Curve25519 public key
+    QString key() const { return payload["key"_ls].toString(); }
 
+    //! \brief Signatures of the key object
+    //!
+    //! The signature is calculated using the process described at
+    //! https://spec.matrix.org/v1.3/appendices/#signing-json
+    auto signatures() const
+    {
+        return fromJson<QHash<QString, QHash<QString, QString>>>(
+            payload["signatures"_ls]);
+    }
 
-template <>
-struct JsonObjectConverter<SignedOneTimeKey> {
-    static void fillFrom(const QJsonObject& jo, SignedOneTimeKey& result)
+    QByteArray signature(QStringView userId, QStringView deviceId) const
     {
-        fromJson(jo.value("key"_ls), result.key);
-        fromJson(jo.value("signatures"_ls), result.signatures);
+        return payload["signatures"_ls][userId]["ed25519:"_ls % deviceId]
+            .toString()
+            .toLatin1();
     }
 
-    static void dumpTo(QJsonObject &jo, const SignedOneTimeKey &result)
+    //! Whether the key is a fallback key
+    bool isFallback() const { return payload["fallback"_ls].toBool(); }
+    auto toJson() const { return payload; }
+    auto toJsonForVerification() const
     {
-        addParam<>(jo, QStringLiteral("key"), result.key);
-        addParam<>(jo, QStringLiteral("signatures"), result.signatures);
+        auto json = payload;
+        json.remove("signatures"_ls);
+        json.remove("unsigned"_ls);
+        return QJsonDocument(json).toJson(QJsonDocument::Compact);
     }
+
+private:
+    QJsonObject payload;
 };
 
+using OneTimeKeys = QHash<QString, std::variant<QString, SignedOneTimeKey>>;
+
 template <typename T>
 class asKeyValueRange
 {
diff --git a/lib/e2ee/qolmaccount.cpp b/lib/e2ee/qolmaccount.cpp
index 476a60bd..ccb191f4 100644
--- a/lib/e2ee/qolmaccount.cpp
+++ b/lib/e2ee/qolmaccount.cpp
@@ -5,6 +5,7 @@
 #include "qolmaccount.h"
 
 #include "connection.h"
+#include "e2ee/qolmsession.h"
 #include "e2ee/qolmutility.h"
 #include "e2ee/qolmutils.h"
 
@@ -12,20 +13,9 @@
 
 #include <QtCore/QRandomGenerator>
 
-using namespace Quotient;
-
-QHash<QString, QString> OneTimeKeys::curve25519() const
-{
-    return keys[Curve25519Key];
-}
+#include <olm/olm.h>
 
-//std::optional<QHash<QString, QString>> OneTimeKeys::get(QString keyType) const
-//{
-//    if (!keys.contains(keyType)) {
-//        return std::nullopt;
-//    }
-//    return keys[keyType];
-//}
+using namespace Quotient;
 
 // Convert olm error to enum
 QOlmError lastError(OlmAccount *account) {
@@ -70,7 +60,7 @@ void QOlmAccount::unpickle(QByteArray &pickled, const PicklingMode &mode)
     }
 }
 
-std::variant<QByteArray, QOlmError> QOlmAccount::pickle(const PicklingMode &mode)
+QOlmExpected<QByteArray> QOlmAccount::pickle(const PicklingMode &mode)
 {
     const QByteArray key = toKey(mode);
     const size_t pickleLength = olm_pickle_account_length(m_account);
@@ -119,20 +109,15 @@ QByteArray QOlmAccount::sign(const QJsonObject &message) const
 QByteArray QOlmAccount::signIdentityKeys() const
 {
     const auto keys = identityKeys();
-    QJsonObject body
-    {
-        {"algorithms", QJsonArray{"m.olm.v1.curve25519-aes-sha2", "m.megolm.v1.aes-sha2"}},
-        {"user_id", m_userId},
-        {"device_id", m_deviceId},
-        {"keys",
-            QJsonObject{
-                {QStringLiteral("curve25519:") + m_deviceId, QString::fromUtf8(keys.curve25519)},
-                {QStringLiteral("ed25519:") + m_deviceId, QString::fromUtf8(keys.ed25519)}
-            }
-        }
-    };
-    return sign(QJsonDocument(body).toJson(QJsonDocument::Compact));
-
+    return sign(QJsonObject {
+        { "algorithms", QJsonArray { "m.olm.v1.curve25519-aes-sha2",
+                                     "m.megolm.v1.aes-sha2" } },
+        { "user_id", m_userId },
+        { "device_id", m_deviceId },
+        { "keys", QJsonObject { { QStringLiteral("curve25519:") + m_deviceId,
+                                  QString::fromUtf8(keys.curve25519) },
+                                { QStringLiteral("ed25519:") + m_deviceId,
+                                  QString::fromUtf8(keys.ed25519) } } } });
 }
 
 size_t QOlmAccount::maxNumberOfOneTimeKeys() const
@@ -140,11 +125,15 @@ size_t QOlmAccount::maxNumberOfOneTimeKeys() const
     return olm_account_max_number_of_one_time_keys(m_account);
 }
 
-size_t QOlmAccount::generateOneTimeKeys(size_t numberOfKeys) const
+size_t QOlmAccount::generateOneTimeKeys(size_t numberOfKeys)
 {
-    const size_t randomLength = olm_account_generate_one_time_keys_random_length(m_account, numberOfKeys);
+    const size_t randomLength =
+        olm_account_generate_one_time_keys_random_length(m_account,
+                                                         numberOfKeys);
     QByteArray randomBuffer = getRandom(randomLength);
-    const auto error = olm_account_generate_one_time_keys(m_account, numberOfKeys, randomBuffer.data(), randomLength);
+    const auto error =
+        olm_account_generate_one_time_keys(m_account, numberOfKeys,
+                                           randomBuffer.data(), randomLength);
 
     if (error == olm_error()) {
         throw lastError(m_account);
@@ -153,49 +142,39 @@ size_t QOlmAccount::generateOneTimeKeys(size_t numberOfKeys) const
     return error;
 }
 
-OneTimeKeys QOlmAccount::oneTimeKeys() const
+UnsignedOneTimeKeys QOlmAccount::oneTimeKeys() const
 {
     const size_t oneTimeKeyLength = olm_account_one_time_keys_length(m_account);
-    QByteArray oneTimeKeysBuffer(oneTimeKeyLength, '0');
+    QByteArray oneTimeKeysBuffer(static_cast<int>(oneTimeKeyLength), '0');
 
-    const auto error = olm_account_one_time_keys(m_account, oneTimeKeysBuffer.data(), oneTimeKeyLength);
+    const auto error = olm_account_one_time_keys(m_account,
+                                                 oneTimeKeysBuffer.data(),
+                                                 oneTimeKeyLength);
     if (error == olm_error()) {
         throw lastError(m_account);
     }
     const auto json = QJsonDocument::fromJson(oneTimeKeysBuffer).object();
-    OneTimeKeys oneTimeKeys;
+    UnsignedOneTimeKeys oneTimeKeys;
     fromJson(json, oneTimeKeys.keys);
     return oneTimeKeys;
 }
 
-QHash<QString, SignedOneTimeKey> QOlmAccount::signOneTimeKeys(const OneTimeKeys &keys) const
+OneTimeKeys QOlmAccount::signOneTimeKeys(const UnsignedOneTimeKeys &keys) const
 {
-    QHash<QString, SignedOneTimeKey> signedOneTimeKeys;
-    for (const auto &keyid : keys.curve25519().keys()) {
-        const auto oneTimeKey = keys.curve25519()[keyid];
-        QByteArray sign = signOneTimeKey(oneTimeKey);
-        signedOneTimeKeys["signed_curve25519:" + keyid] = signedOneTimeKey(oneTimeKey.toUtf8(), sign);
-    }
+    OneTimeKeys signedOneTimeKeys;
+    for (const auto& curveKeys = keys.curve25519();
+         const auto& [keyId, key] : asKeyValueRange(curveKeys))
+        signedOneTimeKeys.insert("signed_curve25519:" % keyId,
+                                 SignedOneTimeKey {
+                                     key, m_userId, m_deviceId,
+                                     sign(QJsonObject { { "key", key } }) });
     return signedOneTimeKeys;
 }
 
-SignedOneTimeKey QOlmAccount::signedOneTimeKey(const QByteArray &key, const QString &signature) const
-{
-    SignedOneTimeKey sign{};
-    sign.key = key;
-    sign.signatures = {{m_userId, {{"ed25519:" + m_deviceId, signature}}}};
-    return sign;
-}
-
-QByteArray QOlmAccount::signOneTimeKey(const QString &key) const
+std::optional<QOlmError> QOlmAccount::removeOneTimeKeys(
+    const QOlmSession& session)
 {
-    QJsonDocument j(QJsonObject{{"key", key}});
-    return sign(j.toJson(QJsonDocument::Compact));
-}
-
-std::optional<QOlmError> QOlmAccount::removeOneTimeKeys(const QOlmSessionPtr &session) const
-{
-    const auto error = olm_remove_one_time_keys(m_account, session->raw());
+    const auto error = olm_remove_one_time_keys(m_account, session.raw());
 
     if (error == olm_error()) {
         return lastError(m_account);
@@ -208,54 +187,47 @@ OlmAccount* QOlmAccount::data() { return m_account; }
 
 DeviceKeys QOlmAccount::deviceKeys() const
 {
-    DeviceKeys deviceKeys;
-    deviceKeys.userId = m_userId;
-    deviceKeys.deviceId = m_deviceId;
-    deviceKeys.algorithms = QStringList {"m.olm.v1.curve25519-aes-sha2", "m.megolm.v1.aes-sha2"};
+    static QStringList Algorithms(SupportedAlgorithms.cbegin(),
+                                  SupportedAlgorithms.cend());
 
     const auto idKeys = identityKeys();
-    deviceKeys.keys["curve25519:" + m_deviceId] = idKeys.curve25519;
-    deviceKeys.keys["ed25519:" + m_deviceId] = idKeys.ed25519;
-
-    const auto sign = signIdentityKeys();
-    deviceKeys.signatures[m_userId]["ed25519:" + m_deviceId] = sign;
-
-    return deviceKeys;
+    return DeviceKeys {
+        .userId = m_userId,
+        .deviceId = m_deviceId,
+        .algorithms = Algorithms,
+        .keys { { "curve25519:" + m_deviceId, idKeys.curve25519 },
+                { "ed25519:" + m_deviceId, idKeys.ed25519 } },
+        .signatures {
+            { m_userId, { { "ed25519:" + m_deviceId, signIdentityKeys() } } } }
+    };
 }
 
-UploadKeysJob *QOlmAccount::createUploadKeyRequest(const OneTimeKeys &oneTimeKeys)
+UploadKeysJob* QOlmAccount::createUploadKeyRequest(
+    const UnsignedOneTimeKeys& oneTimeKeys) const
 {
-    auto keys = deviceKeys();
-
-    if (oneTimeKeys.curve25519().isEmpty()) {
-        return new UploadKeysJob(keys);
-    }
-
-    // Sign & append the one time keys.
-    auto temp = signOneTimeKeys(oneTimeKeys);
-    QHash<QString, QVariant> oneTimeKeysSigned;
-    for (const auto &[keyId, key] : asKeyValueRange(temp)) {
-        oneTimeKeysSigned[keyId] = QVariant::fromValue(toJson(key));
-    }
-
-    return new UploadKeysJob(keys, oneTimeKeysSigned);
+    return new UploadKeysJob(deviceKeys(), signOneTimeKeys(oneTimeKeys));
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmAccount::createInboundSession(const QOlmMessage &preKeyMessage)
+QOlmExpected<QOlmSessionPtr> QOlmAccount::createInboundSession(
+    const QOlmMessage& preKeyMessage)
 {
     Q_ASSERT(preKeyMessage.type() == QOlmMessage::PreKey);
     return QOlmSession::createInboundSession(this, preKeyMessage);
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmAccount::createInboundSessionFrom(const QByteArray &theirIdentityKey, const QOlmMessage &preKeyMessage)
+QOlmExpected<QOlmSessionPtr> QOlmAccount::createInboundSessionFrom(
+    const QByteArray& theirIdentityKey, const QOlmMessage& preKeyMessage)
 {
     Q_ASSERT(preKeyMessage.type() == QOlmMessage::PreKey);
-    return QOlmSession::createInboundSessionFrom(this, theirIdentityKey, preKeyMessage);
+    return QOlmSession::createInboundSessionFrom(this, theirIdentityKey,
+                                                 preKeyMessage);
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmAccount::createOutboundSession(const QByteArray &theirIdentityKey, const QByteArray &theirOneTimeKey)
+QOlmExpected<QOlmSessionPtr> QOlmAccount::createOutboundSession(
+    const QByteArray& theirIdentityKey, const QByteArray& theirOneTimeKey)
 {
-    return QOlmSession::createOutboundSession(this, theirIdentityKey, theirOneTimeKey);
+    return QOlmSession::createOutboundSession(this, theirIdentityKey,
+                                              theirOneTimeKey);
 }
 
 void QOlmAccount::markKeysAsPublished()
@@ -292,10 +264,6 @@ bool Quotient::ed25519VerifySignature(const QString& signingKey,
     QByteArray signingKeyBuf = signingKey.toUtf8();
     QOlmUtility utility;
     auto signatureBuf = signature.toUtf8();
-    auto result = utility.ed25519Verify(signingKeyBuf, canonicalJson, signatureBuf);
-    if (std::holds_alternative<QOlmError>(result)) {
-        return false;
-    }
-
-    return std::get<bool>(result);
+    return utility.ed25519Verify(signingKeyBuf, canonicalJson, signatureBuf)
+        .value_or(false);
 }
diff --git a/lib/e2ee/qolmaccount.h b/lib/e2ee/qolmaccount.h
index 17f43f1a..f2a31314 100644
--- a/lib/e2ee/qolmaccount.h
+++ b/lib/e2ee/qolmaccount.h
@@ -5,21 +5,16 @@
 
 #pragma once
 
-#include "csapi/keys.h"
 #include "e2ee/e2ee.h"
-#include "e2ee/qolmerrors.h"
 #include "e2ee/qolmmessage.h"
-#include "e2ee/qolmsession.h"
-#include <QObject>
 
-struct OlmAccount;
+#include "csapi/keys.h"
 
-namespace Quotient {
+#include <QtCore/QObject>
 
-class QOlmSession;
-class Connection;
+struct OlmAccount;
 
-using QOlmSessionPtr = std::unique_ptr<QOlmSession>;
+namespace Quotient {
 
 //! An olm account manages all cryptographic keys used on a device.
 //! \code{.cpp}
@@ -30,7 +25,7 @@ class QUOTIENT_API QOlmAccount : public QObject
     Q_OBJECT
 public:
     QOlmAccount(const QString &userId, const QString &deviceId, QObject *parent = nullptr);
-    ~QOlmAccount();
+    ~QOlmAccount() override;
 
     //! Creates a new instance of OlmAccount. During the instantiation
     //! the Ed25519 fingerprint key pair and the Curve25519 identity key
@@ -44,7 +39,7 @@ public:
     void unpickle(QByteArray &pickled, const PicklingMode &mode);
 
     //! Serialises an OlmAccount to encrypted Base64.
-    std::variant<QByteArray, QOlmError> pickle(const PicklingMode &mode);
+    QOlmExpected<QByteArray> pickle(const PicklingMode &mode);
 
     //! Returns the account's public identity keys already formatted as JSON
     IdentityKeys identityKeys() const;
@@ -61,40 +56,39 @@ public:
     size_t maxNumberOfOneTimeKeys() const;
 
     //! Generates the supplied number of one time keys.
-    size_t generateOneTimeKeys(size_t numberOfKeys) const;
+    size_t generateOneTimeKeys(size_t numberOfKeys);
 
     //! Gets the OlmAccount's one time keys formatted as JSON.
-    OneTimeKeys oneTimeKeys() const;
+    UnsignedOneTimeKeys oneTimeKeys() const;
 
     //! Sign all one time keys.
-    QHash<QString, SignedOneTimeKey> signOneTimeKeys(const OneTimeKeys &keys) const;
-
-    //! Sign one time key.
-    QByteArray signOneTimeKey(const QString &key) const;
-
-    SignedOneTimeKey signedOneTimeKey(const QByteArray &key, const QString &signature) const;
+    OneTimeKeys signOneTimeKeys(const UnsignedOneTimeKeys &keys) const;
 
-    UploadKeysJob *createUploadKeyRequest(const OneTimeKeys &oneTimeKeys);
+    UploadKeysJob* createUploadKeyRequest(const UnsignedOneTimeKeys& oneTimeKeys) const;
 
     DeviceKeys deviceKeys() const;
 
     //! Remove the one time key used to create the supplied session.
-    [[nodiscard]] std::optional<QOlmError> removeOneTimeKeys(const QOlmSessionPtr &session) const;
+    [[nodiscard]] std::optional<QOlmError> removeOneTimeKeys(
+        const QOlmSession& session);
 
     //! Creates an inbound session for sending/receiving messages from a received 'prekey' message.
     //!
     //! \param message An Olm pre-key message that was encrypted for this account.
-    std::variant<QOlmSessionPtr, QOlmError> createInboundSession(const QOlmMessage &preKeyMessage);
+    QOlmExpected<QOlmSessionPtr> createInboundSession(
+        const QOlmMessage& preKeyMessage);
 
     //! Creates an inbound session for sending/receiving messages from a received 'prekey' message.
     //!
     //! \param theirIdentityKey - The identity key of the Olm account that
     //! encrypted this Olm message.
-    std::variant<QOlmSessionPtr, QOlmError> createInboundSessionFrom(const QByteArray &theirIdentityKey, const QOlmMessage &preKeyMessage);
+    QOlmExpected<QOlmSessionPtr> createInboundSessionFrom(
+        const QByteArray& theirIdentityKey, const QOlmMessage& preKeyMessage);
 
     //! Creates an outbound session for sending messages to a specific
     /// identity and one time key.
-    std::variant<QOlmSessionPtr, QOlmError> createOutboundSession(const QByteArray &theirIdentityKey, const QByteArray &theirOneTimeKey);
+    QOlmExpected<QOlmSessionPtr> createOutboundSession(
+        const QByteArray& theirIdentityKey, const QByteArray& theirOneTimeKey);
 
     void markKeysAsPublished();
 
@@ -103,7 +97,7 @@ public:
     OlmAccount *data();
 
 Q_SIGNALS:
-    void needsSave() const;
+    void needsSave();
 
 private:
     OlmAccount *m_account = nullptr; // owning
diff --git a/lib/e2ee/qolminboundsession.cpp b/lib/e2ee/qolminboundsession.cpp
index 60d871ef..17f06205 100644
--- a/lib/e2ee/qolminboundsession.cpp
+++ b/lib/e2ee/qolminboundsession.cpp
@@ -70,7 +70,8 @@ QByteArray QOlmInboundGroupSession::pickle(const PicklingMode &mode) const
     return pickledBuf;
 }
 
-std::variant<std::unique_ptr<QOlmInboundGroupSession>, QOlmError> QOlmInboundGroupSession::unpickle(const QByteArray &pickled, const PicklingMode &mode)
+QOlmExpected<QOlmInboundGroupSessionPtr> QOlmInboundGroupSession::unpickle(
+    const QByteArray& pickled, const PicklingMode& mode)
 {
     QByteArray pickledBuf = pickled;
     const auto groupSession = olm_inbound_group_session(new uint8_t[olm_inbound_group_session_size()]);
@@ -85,7 +86,8 @@ std::variant<std::unique_ptr<QOlmInboundGroupSession>, QOlmError> QOlmInboundGro
     return std::make_unique<QOlmInboundGroupSession>(groupSession);
 }
 
-std::variant<std::pair<QString, uint32_t>, QOlmError> QOlmInboundGroupSession::decrypt(const QByteArray &message)
+QOlmExpected<std::pair<QByteArray, uint32_t>> QOlmInboundGroupSession::decrypt(
+    const QByteArray& message)
 {
     // This is for capturing the output of olm_group_decrypt
     uint32_t messageIndex = 0;
@@ -114,10 +116,10 @@ std::variant<std::pair<QString, uint32_t>, QOlmError> QOlmInboundGroupSession::d
     QByteArray output(plaintextLen, '0');
     std::memcpy(output.data(), plaintextBuf.data(), plaintextLen);
 
-    return std::make_pair<QString, qint32>(QString(output), messageIndex);
+    return std::make_pair(output, messageIndex);
 }
 
-std::variant<QByteArray, QOlmError> QOlmInboundGroupSession::exportSession(uint32_t messageIndex)
+QOlmExpected<QByteArray> QOlmInboundGroupSession::exportSession(uint32_t messageIndex)
 {
     const auto keyLength = olm_export_inbound_group_session_length(m_groupSession);
     QByteArray keyBuf(keyLength, '0');
@@ -154,9 +156,9 @@ QString QOlmInboundGroupSession::olmSessionId() const
 {
     return m_olmSessionId;
 }
-void QOlmInboundGroupSession::setOlmSessionId(const QString& olmSessionId)
+void QOlmInboundGroupSession::setOlmSessionId(const QString& newOlmSessionId)
 {
-    m_olmSessionId = olmSessionId;
+    m_olmSessionId = newOlmSessionId;
 }
 
 QString QOlmInboundGroupSession::senderId() const
diff --git a/lib/e2ee/qolminboundsession.h b/lib/e2ee/qolminboundsession.h
index 32112b97..1a9b4415 100644
--- a/lib/e2ee/qolminboundsession.h
+++ b/lib/e2ee/qolminboundsession.h
@@ -5,11 +5,8 @@
 #pragma once
 
 #include "e2ee/e2ee.h"
-#include "e2ee/qolmerrors.h"
-#include "olm/olm.h"
 
-#include <memory>
-#include <variant>
+#include <olm/olm.h>
 
 namespace Quotient {
 
@@ -27,14 +24,13 @@ public:
     QByteArray pickle(const PicklingMode &mode) const;
     //! Deserialises from encrypted Base64 that was previously obtained by pickling
     //! an `OlmInboundGroupSession`.
-    static std::variant<std::unique_ptr<QOlmInboundGroupSession>, QOlmError>
-    unpickle(const QByteArray& picked, const PicklingMode& mode);
+    static QOlmExpected<QOlmInboundGroupSessionPtr> unpickle(
+        const QByteArray& pickled, const PicklingMode& mode);
     //! Decrypts ciphertext received for this group session.
-    std::variant<std::pair<QString, uint32_t>, QOlmError> decrypt(
-        const QByteArray& message);
+    QOlmExpected<std::pair<QByteArray, uint32_t> > decrypt(const QByteArray& message);
     //! Export the base64-encoded ratchet key for this session, at the given index,
     //! in a format which can be used by import.
-    std::variant<QByteArray, QOlmError> exportSession(uint32_t messageIndex);
+    QOlmExpected<QByteArray> exportSession(uint32_t messageIndex);
     //! Get the first message index we know how to decrypt.
     uint32_t firstKnownIndex() const;
     //! Get a base64-encoded identifier for this session.
@@ -44,7 +40,7 @@ public:
     //! The olm session that this session was received from.
     //! Required to get the device this session is from.
     QString olmSessionId() const;
-    void setOlmSessionId(const QString& setOlmSessionId);
+    void setOlmSessionId(const QString& newOlmSessionId);
 
     //! The sender of this session.
     QString senderId() const;
diff --git a/lib/e2ee/qolmmessage.cpp b/lib/e2ee/qolmmessage.cpp
index 81b166b0..f9b4a5c2 100644
--- a/lib/e2ee/qolmmessage.cpp
+++ b/lib/e2ee/qolmmessage.cpp
@@ -4,6 +4,8 @@
 
 #include "qolmmessage.h"
 
+#include "util.h"
+
 using namespace Quotient;
 
 QOlmMessage::QOlmMessage(QByteArray ciphertext, QOlmMessage::Type type)
@@ -26,7 +28,7 @@ QOlmMessage::Type QOlmMessage::type() const
 
 QByteArray QOlmMessage::toCiphertext() const
 {
-    return QByteArray(*this);
+    return SLICE(*this, QByteArray);
 }
 
 QOlmMessage QOlmMessage::fromCiphertext(const QByteArray &ciphertext)
diff --git a/lib/e2ee/qolmoutboundsession.cpp b/lib/e2ee/qolmoutboundsession.cpp
index 8852bcf3..a2eff2c8 100644
--- a/lib/e2ee/qolmoutboundsession.cpp
+++ b/lib/e2ee/qolmoutboundsession.cpp
@@ -13,8 +13,7 @@ QOlmError lastError(OlmOutboundGroupSession *session) {
 
 QOlmOutboundGroupSession::QOlmOutboundGroupSession(OlmOutboundGroupSession *session)
     : m_groupSession(session)
-{
-}
+{}
 
 QOlmOutboundGroupSession::~QOlmOutboundGroupSession()
 {
@@ -22,7 +21,7 @@ QOlmOutboundGroupSession::~QOlmOutboundGroupSession()
     delete[](reinterpret_cast<uint8_t *>(m_groupSession));
 }
 
-std::unique_ptr<QOlmOutboundGroupSession> QOlmOutboundGroupSession::create()
+QOlmOutboundGroupSessionPtr QOlmOutboundGroupSession::create()
 {
     auto *olmOutboundGroupSession = olm_outbound_group_session(new uint8_t[olm_outbound_group_session_size()]);
     const auto randomLength = olm_init_outbound_group_session_random_length(olmOutboundGroupSession);
@@ -45,7 +44,7 @@ std::unique_ptr<QOlmOutboundGroupSession> QOlmOutboundGroupSession::create()
     return std::make_unique<QOlmOutboundGroupSession>(olmOutboundGroupSession);
 }
 
-std::variant<QByteArray, QOlmError> QOlmOutboundGroupSession::pickle(const PicklingMode &mode)
+QOlmExpected<QByteArray> QOlmOutboundGroupSession::pickle(const PicklingMode &mode) const
 {
     QByteArray pickledBuf(olm_pickle_outbound_group_session_length(m_groupSession), '0');
     QByteArray key = toKey(mode);
@@ -61,7 +60,7 @@ std::variant<QByteArray, QOlmError> QOlmOutboundGroupSession::pickle(const Pickl
     return pickledBuf;
 }
 
-std::variant<std::unique_ptr<QOlmOutboundGroupSession>, QOlmError> QOlmOutboundGroupSession::unpickle(const QByteArray &pickled, const PicklingMode &mode)
+QOlmExpected<QOlmOutboundGroupSessionPtr> QOlmOutboundGroupSession::unpickle(const QByteArray &pickled, const PicklingMode &mode)
 {
     QByteArray pickledBuf = pickled;
     auto *olmOutboundGroupSession = olm_outbound_group_session(new uint8_t[olm_outbound_group_session_size()]);
@@ -80,7 +79,7 @@ std::variant<std::unique_ptr<QOlmOutboundGroupSession>, QOlmError> QOlmOutboundG
     return std::make_unique<QOlmOutboundGroupSession>(olmOutboundGroupSession);
 }
 
-std::variant<QByteArray, QOlmError> QOlmOutboundGroupSession::encrypt(const QString &plaintext)
+QOlmExpected<QByteArray> QOlmOutboundGroupSession::encrypt(const QString &plaintext) const
 {
     QByteArray plaintextBuf = plaintext.toUtf8();
     const auto messageMaxLength = olm_group_encrypt_message_length(m_groupSession, plaintextBuf.length());
@@ -112,12 +111,13 @@ QByteArray QOlmOutboundGroupSession::sessionId() const
     return idBuffer;
 }
 
-std::variant<QByteArray, QOlmError> QOlmOutboundGroupSession::sessionKey() const
+QOlmExpected<QByteArray> QOlmOutboundGroupSession::sessionKey() const
 {
     const auto keyMaxLength = olm_outbound_group_session_key_length(m_groupSession);
     QByteArray keyBuffer(keyMaxLength, '0');
-    const auto error = olm_outbound_group_session_key(m_groupSession, reinterpret_cast<uint8_t *>(keyBuffer.data()),
-            keyMaxLength);
+    const auto error = olm_outbound_group_session_key(
+        m_groupSession, reinterpret_cast<uint8_t*>(keyBuffer.data()),
+        keyMaxLength);
     if (error == olm_error()) {
         return lastError(m_groupSession);
     }
diff --git a/lib/e2ee/qolmoutboundsession.h b/lib/e2ee/qolmoutboundsession.h
index 10ca35c0..9a82d22a 100644
--- a/lib/e2ee/qolmoutboundsession.h
+++ b/lib/e2ee/qolmoutboundsession.h
@@ -4,10 +4,10 @@
 
 #pragma once
 
-#include "olm/olm.h"
-#include "e2ee/qolmerrors.h"
 #include "e2ee/e2ee.h"
+
 #include <memory>
+#include <olm/olm.h>
 
 namespace Quotient {
 
@@ -19,15 +19,16 @@ public:
     ~QOlmOutboundGroupSession();
     //! Creates a new instance of `QOlmOutboundGroupSession`.
     //! Throw OlmError on errors
-    static std::unique_ptr<QOlmOutboundGroupSession> create();
+    static QOlmOutboundGroupSessionPtr create();
     //! Serialises a `QOlmOutboundGroupSession` to encrypted Base64.
-    std::variant<QByteArray, QOlmError> pickle(const PicklingMode &mode);
+    QOlmExpected<QByteArray> pickle(const PicklingMode &mode) const;
     //! Deserialises from encrypted Base64 that was previously obtained by
     //! pickling a `QOlmOutboundGroupSession`.
-    static std::variant<std::unique_ptr<QOlmOutboundGroupSession>, QOlmError>
-    unpickle(const QByteArray& pickled, const PicklingMode& mode);
+    static QOlmExpected<QOlmOutboundGroupSessionPtr> unpickle(
+        const QByteArray& pickled, const PicklingMode& mode);
+
     //! Encrypts a plaintext message using the session.
-    std::variant<QByteArray, QOlmError> encrypt(const QString &plaintext);
+    QOlmExpected<QByteArray> encrypt(const QString& plaintext) const;
 
     //! Get the current message index for this session.
     //!
@@ -42,7 +43,7 @@ public:
     //!
     //! Each message is sent with a different ratchet key. This function returns the
     //! ratchet key that will be used for the next message.
-    std::variant<QByteArray, QOlmError> sessionKey() const;
+    QOlmExpected<QByteArray> sessionKey() const;
     QOlmOutboundGroupSession(OlmOutboundGroupSession *groupSession);
 
     int messageCount() const;
@@ -56,5 +57,4 @@ private:
     QDateTime m_creationTime = QDateTime::currentDateTime();
 };
 
-using QOlmOutboundGroupSessionPtr = std::unique_ptr<QOlmOutboundGroupSession>;
-}
+} // namespace Quotient
diff --git a/lib/e2ee/qolmsession.cpp b/lib/e2ee/qolmsession.cpp
index e575ff39..2a98d5d8 100644
--- a/lib/e2ee/qolmsession.cpp
+++ b/lib/e2ee/qolmsession.cpp
@@ -3,10 +3,12 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
 
 #include "qolmsession.h"
+
 #include "e2ee/qolmutils.h"
 #include "logging.h"
+
 #include <cstring>
-#include <QDebug>
+#include <olm/olm.h>
 
 using namespace Quotient;
 
@@ -25,7 +27,9 @@ OlmSession* QOlmSession::create()
     return olm_session(new uint8_t[olm_session_size()]);
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmSession::createInbound(QOlmAccount *account, const QOlmMessage &preKeyMessage, bool from, const QString &theirIdentityKey)
+QOlmExpected<QOlmSessionPtr> QOlmSession::createInbound(
+    QOlmAccount* account, const QOlmMessage& preKeyMessage, bool from,
+    const QString& theirIdentityKey)
 {
     if (preKeyMessage.type() != QOlmMessage::PreKey) {
         qCCritical(E2EE) << "The message is not a pre-key in when creating inbound session" << BadMessageFormat;
@@ -51,17 +55,22 @@ std::variant<QOlmSessionPtr, QOlmError> QOlmSession::createInbound(QOlmAccount *
     return std::make_unique<QOlmSession>(olmSession);
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmSession::createInboundSession(QOlmAccount *account, const QOlmMessage &preKeyMessage)
+QOlmExpected<QOlmSessionPtr> QOlmSession::createInboundSession(
+    QOlmAccount* account, const QOlmMessage& preKeyMessage)
 {
     return createInbound(account, preKeyMessage);
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmSession::createInboundSessionFrom(QOlmAccount *account, const QString &theirIdentityKey, const QOlmMessage &preKeyMessage)
+QOlmExpected<QOlmSessionPtr> QOlmSession::createInboundSessionFrom(
+    QOlmAccount* account, const QString& theirIdentityKey,
+    const QOlmMessage& preKeyMessage)
 {
     return createInbound(account, preKeyMessage, true, theirIdentityKey);
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmSession::createOutboundSession(QOlmAccount *account, const QString &theirIdentityKey, const QString &theirOneTimeKey)
+QOlmExpected<QOlmSessionPtr> QOlmSession::createOutboundSession(
+    QOlmAccount* account, const QString& theirIdentityKey,
+    const QString& theirOneTimeKey)
 {
     auto *olmOutboundSession = create();
     const auto randomLen = olm_create_outbound_session_random_length(olmOutboundSession);
@@ -87,12 +96,13 @@ std::variant<QOlmSessionPtr, QOlmError> QOlmSession::createOutboundSession(QOlmA
     return std::make_unique<QOlmSession>(olmOutboundSession);
 }
 
-std::variant<QByteArray, QOlmError> QOlmSession::pickle(const PicklingMode &mode)
+QOlmExpected<QByteArray> QOlmSession::pickle(const PicklingMode &mode) const
 {
     QByteArray pickledBuf(olm_pickle_session_length(m_session), '0');
     QByteArray key = toKey(mode);
     const auto error = olm_pickle_session(m_session, key.data(), key.length(),
-            pickledBuf.data(), pickledBuf.length());
+                                          pickledBuf.data(),
+                                          pickledBuf.length());
 
     if (error == olm_error()) {
         return lastError(m_session);
@@ -103,7 +113,8 @@ std::variant<QByteArray, QOlmError> QOlmSession::pickle(const PicklingMode &mode
     return pickledBuf;
 }
 
-std::variant<QOlmSessionPtr, QOlmError> QOlmSession::unpickle(const QByteArray &pickled, const PicklingMode &mode)
+QOlmExpected<QOlmSessionPtr> QOlmSession::unpickle(const QByteArray& pickled,
+                                                   const PicklingMode& mode)
 {
     QByteArray pickledBuf = pickled;
     auto *olmSession = create();
@@ -138,7 +149,7 @@ QOlmMessage QOlmSession::encrypt(const QString &plaintext)
     return QOlmMessage(messageBuf, messageType);
 }
 
-std::variant<QString, QOlmError> QOlmSession::decrypt(const QOlmMessage &message) const
+QOlmExpected<QByteArray> QOlmSession::decrypt(const QOlmMessage &message) const
 {
     const auto messageType = message.type();
     const auto ciphertext = message.toCiphertext();
@@ -207,45 +218,35 @@ bool QOlmSession::hasReceivedMessage() const
     return olm_session_has_received_message(m_session);
 }
 
-std::variant<bool, QOlmError> QOlmSession::matchesInboundSession(const QOlmMessage &preKeyMessage) const
+bool QOlmSession::matchesInboundSession(const QOlmMessage& preKeyMessage) const
 {
     Q_ASSERT(preKeyMessage.type() == QOlmMessage::Type::PreKey);
     QByteArray oneTimeKeyBuf(preKeyMessage.data());
-    const auto matchesResult = olm_matches_inbound_session(m_session, oneTimeKeyBuf.data(), oneTimeKeyBuf.length());
+    const auto maybeMatches =
+        olm_matches_inbound_session(m_session, oneTimeKeyBuf.data(),
+                                    oneTimeKeyBuf.length());
 
-    if (matchesResult == olm_error()) {
+    if (maybeMatches == olm_error()) {
         return lastError(m_session);
     }
-    switch (matchesResult) {
-        case 0:
-            return false;
-        case 1:
-            return true;
-        default:
-            return QOlmError::Unknown;
-    }
+    return maybeMatches == 1;
 }
-std::variant<bool, QOlmError> QOlmSession::matchesInboundSessionFrom(const QString &theirIdentityKey, const QOlmMessage &preKeyMessage) const
+
+bool QOlmSession::matchesInboundSessionFrom(
+    const QString& theirIdentityKey, const QOlmMessage& preKeyMessage) const
 {
     const auto theirIdentityKeyBuf = theirIdentityKey.toUtf8();
     auto oneTimeKeyMessageBuf = preKeyMessage.toCiphertext();
-    const auto error = olm_matches_inbound_session_from(m_session, theirIdentityKeyBuf.data(), theirIdentityKeyBuf.length(),
-            oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
+    const auto maybeMatches = olm_matches_inbound_session_from(
+        m_session, theirIdentityKeyBuf.data(), theirIdentityKeyBuf.length(),
+        oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
 
-    if (error == olm_error()) {
-        return lastError(m_session);
-    }
-    switch (error) {
-        case 0:
-            return false;
-        case 1:
-            return true;
-        default:
-            return QOlmError::Unknown;
-    }
+    if (maybeMatches == olm_error())
+        qCWarning(E2EE) << "Error matching an inbound session:"
+                        << olm_session_last_error(m_session);
+    return maybeMatches == 1;
 }
 
 QOlmSession::QOlmSession(OlmSession *session)
     : m_session(session)
-{
-}
+{}
diff --git a/lib/e2ee/qolmsession.h b/lib/e2ee/qolmsession.h
index f20c9837..021092c7 100644
--- a/lib/e2ee/qolmsession.h
+++ b/lib/e2ee/qolmsession.h
@@ -4,17 +4,14 @@
 
 #pragma once
 
-#include <QDebug>
-#include <olm/olm.h> // FIXME: OlmSession
 #include "e2ee/e2ee.h"
 #include "e2ee/qolmmessage.h"
 #include "e2ee/qolmerrors.h"
 #include "e2ee/qolmaccount.h"
 
-namespace Quotient {
+struct OlmSession;
 
-class QOlmAccount;
-class QOlmSession;
+namespace Quotient {
 
 //! Either an outbound or inbound session for secure communication.
 class QUOTIENT_API QOlmSession
@@ -22,32 +19,31 @@ class QUOTIENT_API QOlmSession
 public:
     ~QOlmSession();
     //! Creates an inbound session for sending/receiving messages from a received 'prekey' message.
-    static std::variant<std::unique_ptr<QOlmSession>, QOlmError>
-    createInboundSession(QOlmAccount* account, const QOlmMessage& preKeyMessage);
+    static QOlmExpected<QOlmSessionPtr> createInboundSession(
+        QOlmAccount* account, const QOlmMessage& preKeyMessage);
 
-    static std::variant<std::unique_ptr<QOlmSession>, QOlmError>
-    createInboundSessionFrom(QOlmAccount* account,
-                             const QString& theirIdentityKey,
-                             const QOlmMessage& preKeyMessage);
+    static QOlmExpected<QOlmSessionPtr> createInboundSessionFrom(
+        QOlmAccount* account, const QString& theirIdentityKey,
+        const QOlmMessage& preKeyMessage);
 
-    static std::variant<std::unique_ptr<QOlmSession>, QOlmError>
-    createOutboundSession(QOlmAccount* account, const QString& theirIdentityKey,
-                          const QString& theirOneTimeKey);
+    static QOlmExpected<QOlmSessionPtr> createOutboundSession(
+        QOlmAccount* account, const QString& theirIdentityKey,
+        const QString& theirOneTimeKey);
 
     //! Serialises an `QOlmSession` to encrypted Base64.
-    std::variant<QByteArray, QOlmError> pickle(const PicklingMode &mode);
+    QOlmExpected<QByteArray> pickle(const PicklingMode &mode) const;
 
     //! Deserialises from encrypted Base64 that was previously obtained by pickling a `QOlmSession`.
-    static std::variant<std::unique_ptr<QOlmSession>, QOlmError> unpickle(
+    static QOlmExpected<QOlmSessionPtr> unpickle(
         const QByteArray& pickled, const PicklingMode& mode);
 
     //! Encrypts a plaintext message using the session.
     QOlmMessage encrypt(const QString &plaintext);
 
-    //! Decrypts a message using this session. Decoding is lossy, meaing if
+    //! Decrypts a message using this session. Decoding is lossy, meaning if
     //! the decrypted plaintext contains invalid UTF-8 symbols, they will
     //! be returned as `U+FFFD` (�).
-    std::variant<QString, QOlmError> decrypt(const QOlmMessage &message) const;
+    QOlmExpected<QByteArray> decrypt(const QOlmMessage &message) const;
 
     //! Get a base64-encoded identifier for this session.
     QByteArray sessionId() const;
@@ -59,11 +55,10 @@ public:
     bool hasReceivedMessage() const;
 
     //! Checks if the 'prekey' message is for this in-bound session.
-    std::variant<bool, QOlmError> matchesInboundSession(
-        const QOlmMessage& preKeyMessage) const;
+    bool matchesInboundSession(const QOlmMessage& preKeyMessage) const;
 
     //! Checks if the 'prekey' message is for this in-bound session.
-    std::variant<bool, QOlmError> matchesInboundSessionFrom(
+    bool matchesInboundSessionFrom(
         const QString& theirIdentityKey, const QOlmMessage& preKeyMessage) const;
 
     friend bool operator<(const QOlmSession& lhs, const QOlmSession& rhs)
@@ -71,8 +66,7 @@ public:
         return lhs.sessionId() < rhs.sessionId();
     }
 
-    friend bool operator<(const std::unique_ptr<QOlmSession>& lhs,
-                          const std::unique_ptr<QOlmSession>& rhs)
+    friend bool operator<(const QOlmSessionPtr& lhs, const QOlmSessionPtr& rhs)
     {
         return *lhs < *rhs;
     }
@@ -83,7 +77,7 @@ public:
 private:
     //! Helper function for creating new sessions and handling errors.
     static OlmSession* create();
-    static std::variant<std::unique_ptr<QOlmSession>, QOlmError> createInbound(
+    static QOlmExpected<QOlmSessionPtr> createInbound(
         QOlmAccount* account, const QOlmMessage& preKeyMessage,
         bool from = false, const QString& theirIdentityKey = "");
     OlmSession* m_session;
diff --git a/lib/e2ee/qolmutility.cpp b/lib/e2ee/qolmutility.cpp
index 9f09a37f..84559085 100644
--- a/lib/e2ee/qolmutility.cpp
+++ b/lib/e2ee/qolmutility.cpp
@@ -3,8 +3,8 @@
 // SPDX-License-Identifier: LGPL-2.1-or-later
 
 #include "e2ee/qolmutility.h"
-#include "olm/olm.h"
-#include <QDebug>
+
+#include <olm/olm.h>
 
 using namespace Quotient;
 
@@ -40,8 +40,9 @@ QString QOlmUtility::sha256Utf8Msg(const QString &message) const
     return sha256Bytes(message.toUtf8());
 }
 
-std::variant<bool, QOlmError> QOlmUtility::ed25519Verify(const QByteArray &key,
-        const QByteArray &message, const QByteArray &signature)
+QOlmExpected<bool> QOlmUtility::ed25519Verify(const QByteArray& key,
+                                              const QByteArray& message,
+                                              const QByteArray& signature)
 {
     QByteArray signatureBuf(signature.length(), '0');
     std::copy(signature.begin(), signature.end(), signatureBuf.begin());
@@ -57,8 +58,5 @@ std::variant<bool, QOlmError> QOlmUtility::ed25519Verify(const QByteArray &key,
         return error;
     }
 
-    if (ret != 0) {
-        return false;
-    }
-    return true;
+    return !ret; // ret == 0 means success
 }
diff --git a/lib/e2ee/qolmutility.h b/lib/e2ee/qolmutility.h
index a12af49a..5f6bcdc5 100644
--- a/lib/e2ee/qolmutility.h
+++ b/lib/e2ee/qolmutility.h
@@ -4,15 +4,12 @@
 
 #pragma once
 
-#include <variant>
-#include "e2ee/qolmerrors.h"
+#include "e2ee/e2ee.h"
 
 struct OlmUtility;
 
 namespace Quotient {
 
-class QOlmSession;
-
 //! Allows you to make use of crytographic hashing via SHA-2 and
 //! verifying ed25519 signatures.
 class QUOTIENT_API QOlmUtility
@@ -32,7 +29,7 @@ public:
     //! \param key QByteArray The public part of the ed25519 key that signed the message.
     //! \param message QByteArray The message that was signed.
     //! \param signature QByteArray The signature of the message.
-    std::variant<bool, QOlmError> ed25519Verify(const QByteArray &key,
+    QOlmExpected<bool> ed25519Verify(const QByteArray &key,
             const QByteArray &message, const QByteArray &signature);
 
 private:
diff --git a/lib/eventitem.cpp b/lib/eventitem.cpp
index 302ae053..a2e2a156 100644
--- a/lib/eventitem.cpp
+++ b/lib/eventitem.cpp
@@ -8,32 +8,23 @@
 
 using namespace Quotient;
 
-void PendingEventItem::setFileUploaded(const QUrl& remoteUrl)
+void PendingEventItem::setFileUploaded(const FileSourceInfo& uploadedFileData)
 {
     // TODO: eventually we might introduce hasFileContent to RoomEvent,
     // and unify the code below.
     if (auto* rme = getAs<RoomMessageEvent>()) {
         Q_ASSERT(rme->hasFileContent());
-        rme->editContent([remoteUrl](EventContent::TypedBase& ec) {
-            ec.fileInfo()->url = remoteUrl;
+        rme->editContent([&uploadedFileData](EventContent::TypedBase& ec) {
+            ec.fileInfo()->source = uploadedFileData;
         });
     }
     if (auto* rae = getAs<RoomAvatarEvent>()) {
         Q_ASSERT(rae->content().fileInfo());
-        rae->editContent(
-            [remoteUrl](EventContent::FileInfo& fi) { fi.url = remoteUrl; });
-    }
-    setStatus(EventStatus::FileUploaded);
-}
-
-void PendingEventItem::setEncryptedFile(const EncryptedFile& encryptedFile)
-{
-    if (auto* rme = getAs<RoomMessageEvent>()) {
-        Q_ASSERT(rme->hasFileContent());
-        rme->editContent([encryptedFile](EventContent::TypedBase& ec) {
-            ec.fileInfo()->file = encryptedFile;
+        rae->editContent([&uploadedFileData](EventContent::FileInfo& fi) {
+            fi.source = uploadedFileData;
         });
     }
+    setStatus(EventStatus::FileUploaded);
 }
 
 // Not exactly sure why but this helps with the linker not finding
diff --git a/lib/eventitem.h b/lib/eventitem.h
index d8313736..90d9f458 100644
--- a/lib/eventitem.h
+++ b/lib/eventitem.h
@@ -3,18 +3,18 @@
 
 #pragma once
 
-#include "events/stateevent.h"
 #include "quotient_common.h"
 
+#include "events/filesourceinfo.h"
+#include "events/stateevent.h"
+
 #include <any>
 #include <utility>
 
-#include "events/encryptedfile.h"
-
 namespace Quotient {
 
 namespace EventStatus {
-    QUO_NAMESPACE
+    Q_NAMESPACE_EXPORT(QUOTIENT_API)
 
     /** Special marks an event can assume
      *
@@ -22,16 +22,16 @@ namespace EventStatus {
      * All values except Redacted and Hidden are mutually exclusive.
      */
     enum Code {
-        Normal = 0x0, //< No special designation
-        Submitted = 0x01, //< The event has just been submitted for sending
-        FileUploaded = 0x02, //< The file attached to the event has been
-                             // uploaded to the server
-        Departed = 0x03, //< The event has left the client
-        ReachedServer = 0x04, //< The server has received the event
-        SendingFailed = 0x05, //< The server could not receive the event
-        Redacted = 0x08, //< The event has been redacted
-        Replaced = 0x10, //< The event has been replaced
-        Hidden = 0x100, //< The event should not be shown in the timeline
+        Normal = 0x0, ///< No special designation
+        Submitted = 0x01, ///< The event has just been submitted for sending
+        FileUploaded = 0x02, ///< The file attached to the event has been
+                             ///  uploaded to the server
+        Departed = 0x03, ///< The event has left the client
+        ReachedServer = 0x04, ///< The server has received the event
+        SendingFailed = 0x05, ///< The server could not receive the event
+        Redacted = 0x08, ///< The event has been redacted
+        Replaced = 0x10, ///< The event has been replaced
+        Hidden = 0x100, ///< The event should not be shown in the timeline
     };
     Q_ENUM_NS(Code)
 } // namespace EventStatus
@@ -115,8 +115,7 @@ public:
     QString annotation() const { return _annotation; }
 
     void setDeparted() { setStatus(EventStatus::Departed); }
-    void setFileUploaded(const QUrl& remoteUrl);
-    void setEncryptedFile(const EncryptedFile& encryptedFile);
+    void setFileUploaded(const FileSourceInfo &uploadedFileData);
     void setReachedServer(const QString& eventId)
     {
         setStatus(EventStatus::ReachedServer);
diff --git a/lib/events/accountdataevents.h b/lib/events/accountdataevents.h
index 12f1f00b..24c3353c 100644
--- a/lib/events/accountdataevents.h
+++ b/lib/events/accountdataevents.h
@@ -32,7 +32,7 @@ struct JsonObjectConverter<TagRecord> {
         if (orderJv.isDouble())
             rec.order = fromJson<float>(orderJv);
         if (orderJv.isString()) {
-            bool ok;
+            bool ok = false;
             rec.order = orderJv.toString().toFloat(&ok);
             if (!ok)
                 rec.order = none;
@@ -46,27 +46,14 @@ struct JsonObjectConverter<TagRecord> {
 
 using TagsMap = QHash<QString, TagRecord>;
 
-#define DEFINE_SIMPLE_EVENT(_Name, _TypeId, _ContentType, _ContentKey)       \
-    class QUOTIENT_API _Name : public Event {                             \
-    public:                                                                  \
-        using content_type = _ContentType;                                   \
-        DEFINE_EVENT_TYPEID(_TypeId, _Name)                                  \
-        explicit _Name(const QJsonObject& obj) : Event(typeId(), obj) {}     \
-        explicit _Name(const content_type& content)                          \
-            : Event(typeId(), matrixTypeId(),                                \
-                    QJsonObject {                                            \
-                        { QStringLiteral(#_ContentKey), toJson(content) } }) \
-        {}                                                                   \
-        auto _ContentKey() const                                             \
-        {                                                                    \
-            return contentPart<content_type>(#_ContentKey##_ls);             \
-        }                                                                    \
-    };                                                                       \
-    REGISTER_EVENT_TYPE(_Name)                                               \
-    // End of macro
-
-DEFINE_SIMPLE_EVENT(TagEvent, "m.tag", TagsMap, tags)
-DEFINE_SIMPLE_EVENT(ReadMarkerEvent, "m.fully_read", QString, event_id)
-DEFINE_SIMPLE_EVENT(IgnoredUsersEvent, "m.ignored_user_list", QSet<QString>,
+DEFINE_SIMPLE_EVENT(TagEvent, Event, "m.tag", TagsMap, tags)
+DEFINE_SIMPLE_EVENT(ReadMarkerEventImpl, Event, "m.fully_read", QString, eventId)
+class ReadMarkerEvent : public ReadMarkerEventImpl {
+public:
+    using ReadMarkerEventImpl::ReadMarkerEventImpl;
+    [[deprecated("Use ReadMarkerEvent::eventId() instead")]]
+    QString event_id() const { return eventId(); }
+};
+DEFINE_SIMPLE_EVENT(IgnoredUsersEvent, Event, "m.ignored_user_list", QSet<QString>,
                     ignored_users)
 } // namespace Quotient
diff --git a/lib/events/callanswerevent.cpp b/lib/events/callanswerevent.cpp
index be83d9d0..f75f8ad3 100644
--- a/lib/events/callanswerevent.cpp
+++ b/lib/events/callanswerevent.cpp
@@ -14,7 +14,6 @@ m.call.answer
             "type": "answer"
         },
         "call_id": "12345",
-        "lifetime": 60000,
         "version": 0
     },
     "event_id": "$WLGTSEFSEF:localhost",
@@ -33,16 +32,6 @@ CallAnswerEvent::CallAnswerEvent(const QJsonObject& obj)
     qCDebug(EVENTS) << "Call Answer event";
 }
 
-CallAnswerEvent::CallAnswerEvent(const QString& callId, const int lifetime,
-                                 const QString& sdp)
-    : CallEventBase(
-        typeId(), matrixTypeId(), callId, 0,
-        { { QStringLiteral("lifetime"), lifetime },
-          { QStringLiteral("answer"),
-            QJsonObject { { QStringLiteral("type"), QStringLiteral("answer") },
-                          { QStringLiteral("sdp"), sdp } } } })
-{}
-
 CallAnswerEvent::CallAnswerEvent(const QString& callId, const QString& sdp)
     : CallEventBase(
         typeId(), matrixTypeId(), callId, 0,
diff --git a/lib/events/callanswerevent.h b/lib/events/callanswerevent.h
index 8ffe60f2..4d539b85 100644
--- a/lib/events/callanswerevent.h
+++ b/lib/events/callanswerevent.h
@@ -13,14 +13,8 @@ public:
 
     explicit CallAnswerEvent(const QJsonObject& obj);
 
-    explicit CallAnswerEvent(const QString& callId, const int lifetime,
-                             const QString& sdp);
     explicit CallAnswerEvent(const QString& callId, const QString& sdp);
 
-    int lifetime() const
-    {
-        return contentPart<int>("lifetime"_ls);
-    } // FIXME: Omittable<>?
     QString sdp() const
     {
         return contentPart<QJsonObject>("answer"_ls).value("sdp"_ls).toString();
diff --git a/lib/events/callcandidatesevent.h b/lib/events/callcandidatesevent.h
index 74c38f2c..e949f722 100644
--- a/lib/events/callcandidatesevent.h
+++ b/lib/events/callcandidatesevent.h
@@ -23,20 +23,9 @@ public:
                         { { QStringLiteral("candidates"), candidates } })
     {}
 
-    QJsonArray candidates() const
-    {
-        return contentPart<QJsonArray>("candidates"_ls);
-    }
-
-    QString callId() const
-    {
-        return contentPart<QString>("call_id");
-    }
-
-    int version() const
-    {
-        return contentPart<int>("version");
-    }
+    QUO_CONTENT_GETTER(QJsonArray, candidates)
+    QUO_CONTENT_GETTER(QString, callId)
+    QUO_CONTENT_GETTER(int, version)
 };
 
 REGISTER_EVENT_TYPE(CallCandidatesEvent)
diff --git a/lib/events/callinviteevent.cpp b/lib/events/callinviteevent.cpp
index 11d50768..2f26a1cb 100644
--- a/lib/events/callinviteevent.cpp
+++ b/lib/events/callinviteevent.cpp
@@ -33,7 +33,7 @@ CallInviteEvent::CallInviteEvent(const QJsonObject& obj)
     qCDebug(EVENTS) << "Call Invite event";
 }
 
-CallInviteEvent::CallInviteEvent(const QString& callId, const int lifetime,
+CallInviteEvent::CallInviteEvent(const QString& callId, int lifetime,
                                  const QString& sdp)
     : CallEventBase(
         typeId(), matrixTypeId(), callId, 0,
diff --git a/lib/events/callinviteevent.h b/lib/events/callinviteevent.h
index 47362b5c..5b4ca0df 100644
--- a/lib/events/callinviteevent.h
+++ b/lib/events/callinviteevent.h
@@ -13,13 +13,10 @@ public:
 
     explicit CallInviteEvent(const QJsonObject& obj);
 
-    explicit CallInviteEvent(const QString& callId, const int lifetime,
+    explicit CallInviteEvent(const QString& callId, int lifetime,
                              const QString& sdp);
 
-    int lifetime() const
-    {
-        return contentPart<int>("lifetime"_ls);
-    } // FIXME: Omittable<>?
+    QUO_CONTENT_GETTER(int, lifetime)
     QString sdp() const
     {
         return contentPart<QJsonObject>("offer"_ls).value("sdp"_ls).toString();
diff --git a/lib/events/directchatevent.cpp b/lib/events/directchatevent.cpp
index 0ee1f7b0..83bb1e32 100644
--- a/lib/events/directchatevent.cpp
+++ b/lib/events/directchatevent.cpp
@@ -3,8 +3,6 @@
 
 #include "directchatevent.h"
 
-#include <QtCore/QJsonArray>
-
 using namespace Quotient;
 
 QMultiHash<QString, QString> DirectChatEvent::usersToDirectChats() const
diff --git a/lib/events/encryptedevent.cpp b/lib/events/encryptedevent.cpp
index 3af3d6ff..ec00ad4c 100644
--- a/lib/events/encryptedevent.cpp
+++ b/lib/events/encryptedevent.cpp
@@ -49,14 +49,16 @@ RoomEventPtr EncryptedEvent::createDecrypted(const QString &decrypted) const
     eventObject["event_id"] = id();
     eventObject["sender"] = senderId();
     eventObject["origin_server_ts"] = originTimestamp().toMSecsSinceEpoch();
-    if (const auto relatesToJson = contentPart("m.relates_to"_ls); !relatesToJson.isUndefined()) {
+    if (const auto relatesToJson = contentPart<QJsonObject>("m.relates_to"_ls);
+        !relatesToJson.isEmpty()) {
         auto content = eventObject["content"].toObject();
-        content["m.relates_to"] = relatesToJson.toObject();
+        content["m.relates_to"] = relatesToJson;
         eventObject["content"] = content;
     }
-    if (const auto redactsJson = unsignedPart("redacts"_ls); !redactsJson.isUndefined()) {
+    if (const auto redactsJson = unsignedPart<QString>("redacts"_ls);
+        !redactsJson.isEmpty()) {
         auto unsign = eventObject["unsigned"].toObject();
-        unsign["redacts"] = redactsJson.toString();
+        unsign["redacts"] = redactsJson;
         eventObject["unsigned"] = unsign;
     }
     return loadEvent<RoomEvent>(eventObject);
@@ -64,7 +66,7 @@ RoomEventPtr EncryptedEvent::createDecrypted(const QString &decrypted) const
 
 void EncryptedEvent::setRelation(const QJsonObject& relation)
 {
-    auto content = editJson()["content"_ls].toObject();
+    auto content = contentJson();
     content["m.relates_to"] = relation;
     editJson()["content"] = content;
 }
diff --git a/lib/events/encryptedevent.h b/lib/events/encryptedevent.h
index bfacdec9..ddd5e415 100644
--- a/lib/events/encryptedevent.h
+++ b/lib/events/encryptedevent.h
@@ -58,8 +58,6 @@ public:
     RoomEventPtr createDecrypted(const QString &decrypted) const;
 
     void setRelation(const QJsonObject& relation);
-
-    bool isVerified();
 };
 REGISTER_EVENT_TYPE(EncryptedEvent)
 
diff --git a/lib/events/encryptedfile.cpp b/lib/events/encryptedfile.cpp
deleted file mode 100644
index bb4e26c7..00000000
--- a/lib/events/encryptedfile.cpp
+++ /dev/null
@@ -1,118 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
-//
-// SPDX-License-Identifier: LGPL-2.1-or-later
-
-#include "encryptedfile.h"
-#include "logging.h"
-
-#ifdef Quotient_E2EE_ENABLED
-#include <openssl/evp.h>
-#include <QtCore/QCryptographicHash>
-#include "e2ee/qolmutils.h"
-#endif
-
-using namespace Quotient;
-
-QByteArray EncryptedFile::decryptFile(const QByteArray& ciphertext) const
-{
-#ifdef Quotient_E2EE_ENABLED
-    auto _key = key.k;
-    const auto keyBytes = QByteArray::fromBase64(
-        _key.replace(u'_', u'/').replace(u'-', u'+').toLatin1());
-    const auto sha256 = QByteArray::fromBase64(hashes["sha256"].toLatin1());
-    if (sha256
-        != QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
-        qCWarning(E2EE) << "Hash verification failed for file";
-        return {};
-    }
-    {
-        int length;
-        auto* ctx = EVP_CIPHER_CTX_new();
-        QByteArray plaintext(ciphertext.size() + EVP_MAX_BLOCK_LENGTH
-                                 - 1,
-                             '\0');
-        EVP_DecryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr,
-                           reinterpret_cast<const unsigned char*>(
-                               keyBytes.data()),
-                           reinterpret_cast<const unsigned char*>(
-                               QByteArray::fromBase64(iv.toLatin1()).data()));
-        EVP_DecryptUpdate(
-            ctx, reinterpret_cast<unsigned char*>(plaintext.data()), &length,
-            reinterpret_cast<const unsigned char*>(ciphertext.data()),
-            ciphertext.size());
-        EVP_DecryptFinal_ex(ctx,
-                            reinterpret_cast<unsigned char*>(plaintext.data())
-                                + length,
-                            &length);
-        EVP_CIPHER_CTX_free(ctx);
-        return plaintext.left(ciphertext.size());
-    }
-#else
-    qWarning(MAIN) << "This build of libQuotient doesn't support E2EE, "
-                      "cannot decrypt the file";
-    return ciphertext;
-#endif
-}
-
-std::pair<EncryptedFile, QByteArray> EncryptedFile::encryptFile(const QByteArray &plainText)
-{
-#ifdef Quotient_E2EE_ENABLED
-    QByteArray k = getRandom(32);
-    auto kBase64 = k.toBase64();
-    QByteArray iv = getRandom(16);
-    JWK key = {"oct"_ls, {"encrypt"_ls, "decrypt"_ls}, "A256CTR"_ls, QString(k.toBase64()).replace(u'/', u'_').replace(u'+', u'-').left(kBase64.indexOf('=')), true};
-
-    int length;
-    auto* ctx = EVP_CIPHER_CTX_new();
-    QByteArray cipherText(plainText.size(), plainText.size() + EVP_MAX_BLOCK_LENGTH - 1);
-    EVP_EncryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr, reinterpret_cast<const unsigned char*>(k.data()),reinterpret_cast<const unsigned char*>(iv.data()));
-    EVP_EncryptUpdate(ctx, reinterpret_cast<unsigned char*>(cipherText.data()), &length, reinterpret_cast<const unsigned char*>(plainText.data()), plainText.size());
-    EVP_EncryptFinal_ex(ctx, reinterpret_cast<unsigned char*>(cipherText.data()) + length, &length);
-    EVP_CIPHER_CTX_free(ctx);
-
-    auto hash = QCryptographicHash::hash(cipherText, QCryptographicHash::Sha256).toBase64();
-    auto ivBase64 = iv.toBase64();
-    EncryptedFile file = {{}, key, ivBase64.left(ivBase64.indexOf('=')), {{QStringLiteral("sha256"), hash.left(hash.indexOf('='))}}, "v2"_ls};
-    return {file, cipherText};
-#else
-    return {{}, {}};
-#endif
-}
-
-void JsonObjectConverter<EncryptedFile>::dumpTo(QJsonObject& jo,
-                                                const EncryptedFile& pod)
-{
-    addParam<>(jo, QStringLiteral("url"), pod.url);
-    addParam<>(jo, QStringLiteral("key"), pod.key);
-    addParam<>(jo, QStringLiteral("iv"), pod.iv);
-    addParam<>(jo, QStringLiteral("hashes"), pod.hashes);
-    addParam<>(jo, QStringLiteral("v"), pod.v);
-}
-
-void JsonObjectConverter<EncryptedFile>::fillFrom(const QJsonObject& jo,
-                                                  EncryptedFile& pod)
-{
-    fromJson(jo.value("url"_ls), pod.url);
-    fromJson(jo.value("key"_ls), pod.key);
-    fromJson(jo.value("iv"_ls), pod.iv);
-    fromJson(jo.value("hashes"_ls), pod.hashes);
-    fromJson(jo.value("v"_ls), pod.v);
-}
-
-void JsonObjectConverter<JWK>::dumpTo(QJsonObject &jo, const JWK &pod)
-{
-    addParam<>(jo, QStringLiteral("kty"), pod.kty);
-    addParam<>(jo, QStringLiteral("key_ops"), pod.keyOps);
-    addParam<>(jo, QStringLiteral("alg"), pod.alg);
-    addParam<>(jo, QStringLiteral("k"), pod.k);
-    addParam<>(jo, QStringLiteral("ext"), pod.ext);
-}
-
-void JsonObjectConverter<JWK>::fillFrom(const QJsonObject &jo, JWK &pod)
-{
-    fromJson(jo.value("kty"_ls), pod.kty);
-    fromJson(jo.value("key_ops"_ls), pod.keyOps);
-    fromJson(jo.value("alg"_ls), pod.alg);
-    fromJson(jo.value("k"_ls), pod.k);
-    fromJson(jo.value("ext"_ls), pod.ext);
-}
diff --git a/lib/events/encryptedfile.h b/lib/events/encryptedfile.h
deleted file mode 100644
index b2808395..00000000
--- a/lib/events/encryptedfile.h
+++ /dev/null
@@ -1,63 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
-//
-// SPDX-License-Identifier: LGPl-2.1-or-later
-
-#pragma once
-
-#include "converters.h"
-
-namespace Quotient {
-/**
- * JSON Web Key object as specified in
- * https://spec.matrix.org/unstable/client-server-api/#extensions-to-mroommessage-msgtypes
- * The only currently relevant member is `k`, the rest needs to be set to the defaults specified in the spec.
- */
-struct JWK
-{
-    Q_GADGET
-    Q_PROPERTY(QString kty MEMBER kty CONSTANT)
-    Q_PROPERTY(QStringList keyOps MEMBER keyOps CONSTANT)
-    Q_PROPERTY(QString alg MEMBER alg CONSTANT)
-    Q_PROPERTY(QString k MEMBER k CONSTANT)
-    Q_PROPERTY(bool ext MEMBER ext CONSTANT)
-
-public:
-    QString kty;
-    QStringList keyOps;
-    QString alg;
-    QString k;
-    bool ext;
-};
-
-struct QUOTIENT_API EncryptedFile
-{
-    Q_GADGET
-    Q_PROPERTY(QUrl url MEMBER url CONSTANT)
-    Q_PROPERTY(JWK key MEMBER key CONSTANT)
-    Q_PROPERTY(QString iv MEMBER iv CONSTANT)
-    Q_PROPERTY(QHash<QString, QString> hashes MEMBER hashes CONSTANT)
-    Q_PROPERTY(QString v MEMBER v CONSTANT)
-
-public:
-    QUrl url;
-    JWK key;
-    QString iv;
-    QHash<QString, QString> hashes;
-    QString v;
-
-    QByteArray decryptFile(const QByteArray &ciphertext) const;
-    static std::pair<EncryptedFile, QByteArray> encryptFile(const QByteArray& plainText);
-};
-
-template <>
-struct QUOTIENT_API JsonObjectConverter<EncryptedFile> {
-    static void dumpTo(QJsonObject& jo, const EncryptedFile& pod);
-    static void fillFrom(const QJsonObject& jo, EncryptedFile& pod);
-};
-
-template <>
-struct QUOTIENT_API JsonObjectConverter<JWK> {
-    static void dumpTo(QJsonObject& jo, const JWK& pod);
-    static void fillFrom(const QJsonObject& jo, JWK& pod);
-};
-} // namespace Quotient
diff --git a/lib/events/encryptionevent.cpp b/lib/events/encryptionevent.cpp
index 6272c668..8872447b 100644
--- a/lib/events/encryptionevent.cpp
+++ b/lib/events/encryptionevent.cpp
@@ -6,52 +6,47 @@
 
 #include "e2ee/e2ee.h"
 
-#include <array>
+using namespace Quotient;
 
-namespace Quotient {
-static const std::array<QString, 1> encryptionStrings = {
-    { MegolmV1AesSha2AlgoKey }
-};
+static constexpr std::array encryptionStrings { MegolmV1AesSha2AlgoKey };
 
 template <>
-struct JsonConverter<EncryptionType> {
-    static EncryptionType load(const QJsonValue& jv)
-    {
-        const auto& encryptionString = jv.toString();
-        for (auto it = encryptionStrings.begin(); it != encryptionStrings.end();
-             ++it)
-            if (encryptionString == *it)
-                return EncryptionType(it - encryptionStrings.begin());
-
-        if (!encryptionString.isEmpty())
-            qCWarning(EVENTS) << "Unknown EncryptionType: " << encryptionString;
-        return EncryptionType::Undefined;
-    }
-};
-} // namespace Quotient
-
-using namespace Quotient;
+EncryptionType Quotient::fromJson(const QJsonValue& jv)
+{
+    const auto& encryptionString = jv.toString();
+    for (auto it = encryptionStrings.begin(); it != encryptionStrings.end();
+         ++it)
+        if (encryptionString == *it)
+            return EncryptionType(it - encryptionStrings.begin());
+
+    if (!encryptionString.isEmpty())
+        qCWarning(EVENTS) << "Unknown EncryptionType: " << encryptionString;
+    return EncryptionType::Undefined;
+}
 
 EncryptionEventContent::EncryptionEventContent(const QJsonObject& json)
-    : encryption(fromJson<EncryptionType>(json[AlgorithmKeyL]))
+    : encryption(fromJson<Quotient::EncryptionType>(json[AlgorithmKeyL]))
     , algorithm(sanitized(json[AlgorithmKeyL].toString()))
-    , rotationPeriodMs(json[RotationPeriodMsKeyL].toInt(604800000))
-    , rotationPeriodMsgs(json[RotationPeriodMsgsKeyL].toInt(100))
-{}
+{
+    // NB: fillFromJson only fills the variable if the JSON key exists
+    fillFromJson<int>(json[RotationPeriodMsKeyL], rotationPeriodMs);
+    fillFromJson<int>(json[RotationPeriodMsgsKeyL], rotationPeriodMsgs);
+}
 
-EncryptionEventContent::EncryptionEventContent(EncryptionType et)
+EncryptionEventContent::EncryptionEventContent(Quotient::EncryptionType et)
     : encryption(et)
 {
-    if(encryption != Undefined) {
-        algorithm = encryptionStrings[encryption];
+    if(encryption != Quotient::EncryptionType::Undefined) {
+        algorithm = encryptionStrings[static_cast<size_t>(encryption)];
     }
 }
 
-void EncryptionEventContent::fillJson(QJsonObject* o) const
+QJsonObject EncryptionEventContent::toJson() const
 {
-    Q_ASSERT(o);
-    if (encryption != EncryptionType::Undefined)
-        o->insert(AlgorithmKey, algorithm);
-    o->insert(RotationPeriodMsKey, rotationPeriodMs);
-    o->insert(RotationPeriodMsgsKey, rotationPeriodMsgs);
+    QJsonObject o;
+    if (encryption != Quotient::EncryptionType::Undefined)
+        o.insert(AlgorithmKey, algorithm);
+    o.insert(RotationPeriodMsKey, rotationPeriodMs);
+    o.insert(RotationPeriodMsgsKey, rotationPeriodMsgs);
+    return o;
 }
diff --git a/lib/events/encryptionevent.h b/lib/events/encryptionevent.h
index 124ced33..91452c3f 100644
--- a/lib/events/encryptionevent.h
+++ b/lib/events/encryptionevent.h
@@ -4,57 +4,49 @@
 
 #pragma once
 
-#include "eventcontent.h"
-#include "stateevent.h"
 #include "quotient_common.h"
+#include "stateevent.h"
 
 namespace Quotient {
-class QUOTIENT_API EncryptionEventContent : public EventContent::Base {
+class QUOTIENT_API EncryptionEventContent {
 public:
-    enum EncryptionType : size_t { MegolmV1AesSha2 = 0, Undefined };
+    using EncryptionType
+        [[deprecated("Use Quotient::EncryptionType instead")]] =
+            Quotient::EncryptionType;
 
-    QUO_IMPLICIT EncryptionEventContent(EncryptionType et);
-    [[deprecated("This constructor will require explicit EncryptionType soon")]] //
-    explicit EncryptionEventContent()
-        : EncryptionEventContent(Undefined)
-    {}
+    // NOLINTNEXTLINE(google-explicit-constructor)
+    QUO_IMPLICIT EncryptionEventContent(Quotient::EncryptionType et);
     explicit EncryptionEventContent(const QJsonObject& json);
 
-    EncryptionType encryption;
-    QString algorithm;
-    int rotationPeriodMs;
-    int rotationPeriodMsgs;
+    QJsonObject toJson() const;
 
-protected:
-    void fillJson(QJsonObject* o) const override;
+    Quotient::EncryptionType encryption;
+    QString algorithm {};
+    int rotationPeriodMs = 604'800'000;
+    int rotationPeriodMsgs = 100;
 };
 
-using EncryptionType = EncryptionEventContent::EncryptionType;
-
 class QUOTIENT_API EncryptionEvent : public StateEvent<EncryptionEventContent> {
-    Q_GADGET
 public:
     DEFINE_EVENT_TYPEID("m.room.encryption", EncryptionEvent)
 
-    using EncryptionType = EncryptionEventContent::EncryptionType;
-    Q_ENUM(EncryptionType)
+    using EncryptionType
+        [[deprecated("Use Quotient::EncryptionType instead")]] =
+            Quotient::EncryptionType;
 
     explicit EncryptionEvent(const QJsonObject& obj)
         : StateEvent(typeId(), obj)
     {}
-    [[deprecated("This constructor will require an explicit parameter soon")]] //
-//    explicit EncryptionEvent()
-//        : EncryptionEvent(QJsonObject())
-//    {}
     explicit EncryptionEvent(EncryptionEventContent&& content)
         : StateEvent(typeId(), matrixTypeId(), QString(), std::move(content))
     {}
 
-    EncryptionType encryption() const { return content().encryption; }
-
+    Quotient::EncryptionType encryption() const { return content().encryption; }
     QString algorithm() const { return content().algorithm; }
     int rotationPeriodMs() const { return content().rotationPeriodMs; }
     int rotationPeriodMsgs() const { return content().rotationPeriodMsgs; }
+
+    bool useEncryption() const { return !algorithm().isEmpty(); }
 };
 REGISTER_EVENT_TYPE(EncryptionEvent)
 } // namespace Quotient
diff --git a/lib/events/event.cpp b/lib/events/event.cpp
index 4c304a3c..1f1eebaa 100644
--- a/lib/events/event.cpp
+++ b/lib/events/event.cpp
@@ -29,7 +29,7 @@ Event::Event(Type type, const QJsonObject& json) : _type(type), _json(json)
 }
 
 Event::Event(Type type, event_mtype_t matrixType, const QJsonObject& contentJson)
-    : Event(type, basicEventJson(matrixType, contentJson))
+    : Event(type, basicJson(matrixType, contentJson))
 {}
 
 Event::~Event() = default;
diff --git a/lib/events/event.h b/lib/events/event.h
index 113fa3fa..b7454337 100644
--- a/lib/events/event.h
+++ b/lib/events/event.h
@@ -48,13 +48,6 @@ const QString RoomIdKey { RoomIdKeyL };
 const QString UnsignedKey { UnsignedKeyL };
 const QString StateKeyKey { StateKeyKeyL };
 
-/// Make a minimal correct Matrix event JSON
-inline QJsonObject basicEventJson(const QString& matrixType,
-                                  const QJsonObject& content)
-{
-    return { { TypeKey, matrixType }, { ContentKey, content } };
-}
-
 // === Event types ===
 
 using event_type_t = QLatin1String;
@@ -193,6 +186,13 @@ public:
     Event& operator=(Event&&) = delete;
     virtual ~Event();
 
+    /// Make a minimal correct Matrix event JSON
+    static QJsonObject basicJson(const QString& matrixType,
+                                 const QJsonObject& content)
+    {
+        return { { TypeKey, matrixType }, { ContentKey, content } };
+    }
+
     Type type() const { return _type; }
     QString matrixType() const;
     [[deprecated("Use fullJson() and stringify it with QJsonDocument::toJson() "
@@ -212,7 +212,7 @@ public:
 
     const QJsonObject contentJson() const;
 
-    template <typename T = QJsonValue, typename KeyT>
+    template <typename T, typename KeyT>
     const T contentPart(KeyT&& key) const
     {
         return fromJson<T>(contentJson()[std::forward<KeyT>(key)]);
@@ -227,7 +227,7 @@ public:
 
     const QJsonObject unsignedJson() const;
 
-    template <typename T = QJsonValue, typename KeyT>
+    template <typename T, typename KeyT>
     const T unsignedPart(KeyT&& key) const
     {
         return fromJson<T>(unsignedJson()[std::forward<KeyT>(key)]);
@@ -258,6 +258,21 @@ template <typename EventT>
 using EventsArray = std::vector<event_ptr_tt<EventT>>;
 using Events = EventsArray<Event>;
 
+//! \brief Define an inline method obtaining a content part
+//!
+//! This macro adds a const method that extracts a JSON value at the key
+//! <tt>toSnakeCase(PartName_)</tt> (sic) and converts it to the type
+//! \p PartType_. Effectively, the generated method is an equivalent of
+//! \code
+//! contentPart<PartType_>(Quotient::toSnakeCase(#PartName_##_ls));
+//! \endcode
+#define QUO_CONTENT_GETTER(PartType_, PartName_)                  \
+    PartType_ PartName_() const                                   \
+    {                                                             \
+        static const auto JsonKey = toSnakeCase(#PartName_##_ls); \
+        return contentPart<PartType_>(JsonKey);                   \
+    }
+
 // === Facilities for event class definitions ===
 
 // This macro should be used in a public section of an event class to
@@ -278,6 +293,32 @@ using Events = EventsArray<Event>;
         Type_::factory.addMethod<Type_>();                        \
     // End of macro
 
+/// \brief Define a new event class with a single key-value pair in the content
+///
+/// This macro defines a new event class \p Name_ derived from \p Base_,
+/// with Matrix event type \p TypeId_, providing a getter named \p GetterName_
+/// for a single value of type \p ValueType_ inside the event content.
+/// To retrieve the value the getter uses a JSON key name that corresponds to
+/// its own (getter's) name but written in snake_case. \p GetterName_ must be
+/// in camelCase, no quotes (an identifier, not a literal).
+#define DEFINE_SIMPLE_EVENT(Name_, Base_, TypeId_, ValueType_, GetterName_)     \
+    class QUOTIENT_API Name_ : public Base_ {                                   \
+    public:                                                                     \
+        using content_type = ValueType_;                                        \
+        DEFINE_EVENT_TYPEID(TypeId_, Name_)                                     \
+        explicit Name_(const QJsonObject& obj) : Base_(TypeId, obj) {}          \
+        explicit Name_(const content_type& content)                             \
+            : Name_(Base_::basicJson(TypeId, { { JsonKey, toJson(content) } })) \
+        {}                                                                      \
+        auto GetterName_() const                                                \
+        {                                                                       \
+            return contentPart<content_type>(JsonKey);                          \
+        }                                                                       \
+        static inline const auto JsonKey = toSnakeCase(#GetterName_##_ls);      \
+    };                                                                          \
+    REGISTER_EVENT_TYPE(Name_)                                                  \
+    // End of macro
+
 // === is<>(), eventCast<>() and switchOnType<>() ===
 
 template <class EventT>
@@ -291,65 +332,72 @@ inline bool isUnknown(const Event& e)
     return e.type() == UnknownEventTypeId;
 }
 
+//! \brief Cast the event pointer down in a type-safe way
+//!
+//! Checks that the event \p eptr points to actually is of the requested type
+//! and returns a (plain) pointer to the event downcast to that type. \p eptr
+//! can be either "dumb" (BaseEventT*) or "smart" (`event_ptr_tt<>`). This
+//! overload doesn't affect the event ownership - if the original pointer owns
+//! the event it must outlive the downcast pointer to keep it from dangling.
 template <class EventT, typename BasePtrT>
 inline auto eventCast(const BasePtrT& eptr)
     -> decltype(static_cast<EventT*>(&*eptr))
 {
-    Q_ASSERT(eptr);
-    return is<std::decay_t<EventT>>(*eptr) ? static_cast<EventT*>(&*eptr)
-                                           : nullptr;
+    return eptr && is<std::decay_t<EventT>>(*eptr)
+               ? static_cast<EventT*>(&*eptr)
+               : nullptr;
 }
 
-// A trivial generic catch-all "switch"
-template <class BaseEventT, typename FnT>
-inline auto switchOnType(const BaseEventT& event, FnT&& fn)
-    -> decltype(fn(event))
+//! \brief Cast the event pointer down in a type-safe way, with moving
+//!
+//! Checks that the event \p eptr points to actually is of the requested type;
+//! if (and only if) it is, releases the pointer, downcasts it to the requested
+//! event type and returns a new smart pointer wrapping the downcast one.
+//! Unlike the non-moving eventCast() overload, this one only accepts a smart
+//! pointer, and that smart pointer should be an rvalue (either a temporary,
+//! or as a result of std::move()). The ownership, respectively, is transferred
+//! to the new pointer; the original smart pointer is reset to nullptr, as is
+//! normal for `unique_ptr<>::release()`.
+//! \note If \p eptr's event type does not match \p EventT it retains ownership
+//!       after calling this overload; if it is a temporary, this normally
+//!       leads to the event getting deleted along with the end of
+//!       the temporary's lifetime.
+template <class EventT, typename BaseEventT>
+inline auto eventCast(event_ptr_tt<BaseEventT>&& eptr)
 {
-    return fn(event);
+    return eptr && is<std::decay_t<EventT>>(*eptr)
+               ? event_ptr_tt<EventT>(static_cast<EventT*>(eptr.release()))
+               : nullptr;
 }
 
 namespace _impl {
-    // Using bool instead of auto below because auto apparently upsets MSVC
-    template <class BaseT, typename FnT>
-    constexpr bool needs_downcast =
-        std::is_base_of_v<BaseT, std::decay_t<fn_arg_t<FnT>>>
-        && !std::is_same_v<BaseT, std::decay_t<fn_arg_t<FnT>>>;
+    template <typename FnT, class BaseT>
+    concept Invocable_With_Downcast =
+        std::is_base_of_v<BaseT, std::remove_cvref_t<fn_arg_t<FnT>>>;
 }
 
-// A trivial type-specific "switch" for a void function
-template <class BaseT, typename FnT>
-inline auto switchOnType(const BaseT& event, FnT&& fn)
-    -> std::enable_if_t<_impl::needs_downcast<BaseT, FnT>
-                        && std::is_void_v<fn_return_t<FnT>>>
+template <class BaseT, typename TailT>
+inline auto switchOnType(const BaseT& event, TailT&& tail)
 {
-    using event_type = fn_arg_t<FnT>;
-    if (is<std::decay_t<event_type>>(event))
-        fn(static_cast<event_type>(event));
-}
-
-// A trivial type-specific "switch" for non-void functions with an optional
-// default value; non-voidness is guarded by defaultValue type
-template <class BaseT, typename FnT>
-inline auto switchOnType(const BaseT& event, FnT&& fn,
-                         fn_return_t<FnT>&& defaultValue = {})
-    -> std::enable_if_t<_impl::needs_downcast<BaseT, FnT>, fn_return_t<FnT>>
-{
-    using event_type = fn_arg_t<FnT>;
-    if (is<std::decay_t<event_type>>(event))
-        return fn(static_cast<event_type>(event));
-    return std::move(defaultValue);
+    if constexpr (std::is_invocable_v<TailT, BaseT>) {
+        return tail(event);
+    } else if constexpr (_impl::Invocable_With_Downcast<TailT, BaseT>) {
+        using event_type = fn_arg_t<TailT>;
+        if (is<std::decay_t<event_type>>(event))
+            return tail(static_cast<event_type>(event));
+        return std::invoke_result_t<TailT, event_type>(); // Default-constructed
+    } else { // Treat it as a value to return
+        return std::forward<TailT>(tail);
+    }
 }
 
-// A switch for a chain of 2 or more functions
-template <class BaseT, typename FnT1, typename FnT2, typename... FnTs>
-inline std::common_type_t<fn_return_t<FnT1>, fn_return_t<FnT2>>
-switchOnType(const BaseT& event, FnT1&& fn1, FnT2&& fn2, FnTs&&... fns)
+template <class BaseT, typename FnT1, typename... FnTs>
+inline auto switchOnType(const BaseT& event, FnT1&& fn1, FnTs&&... fns)
 {
     using event_type1 = fn_arg_t<FnT1>;
     if (is<std::decay_t<event_type1>>(event))
-        return fn1(static_cast<event_type1&>(event));
-    return switchOnType(event, std::forward<FnT2>(fn2),
-                        std::forward<FnTs>(fns)...);
+        return fn1(static_cast<event_type1>(event));
+    return switchOnType(event, std::forward<FnTs>(fns)...);
 }
 
 template <class BaseT, typename... FnTs>
@@ -364,8 +412,8 @@ inline auto visit(const BaseT& event, FnTs&&... fns)
 // TODO: replace with ranges::for_each once all standard libraries have it
 template <typename RangeT, typename... FnTs>
 inline auto visitEach(RangeT&& events, FnTs&&... fns)
-    -> std::enable_if_t<std::is_void_v<
-        decltype(switchOnType(**begin(events), std::forward<FnTs>(fns)...))>>
+    requires std::is_void_v<
+        decltype(switchOnType(**begin(events), std::forward<FnTs>(fns)...))>
 {
     for (auto&& evtPtr: events)
         switchOnType(*evtPtr, std::forward<FnTs>(fns)...);
diff --git a/lib/events/eventcontent.cpp b/lib/events/eventcontent.cpp
index 9d7edf20..8db3b7e3 100644
--- a/lib/events/eventcontent.cpp
+++ b/lib/events/eventcontent.cpp
@@ -15,26 +15,25 @@ using std::move;
 QJsonObject Base::toJson() const
 {
     QJsonObject o;
-    fillJson(&o);
+    fillJson(o);
     return o;
 }
 
-FileInfo::FileInfo(const QFileInfo &fi)
-    : mimeType(QMimeDatabase().mimeTypeForFile(fi))
-    , url(QUrl::fromLocalFile(fi.filePath()))
-    , payloadSize(fi.size())
-    , originalName(fi.fileName())
+FileInfo::FileInfo(const QFileInfo& fi)
+    : source(QUrl::fromLocalFile(fi.filePath())),
+      mimeType(QMimeDatabase().mimeTypeForFile(fi)),
+      payloadSize(fi.size()),
+      originalName(fi.fileName())
 {
     Q_ASSERT(fi.isFile());
 }
 
-FileInfo::FileInfo(QUrl u, qint64 payloadSize, const QMimeType& mimeType,
-                   Omittable<EncryptedFile> file, QString originalFilename)
-    : mimeType(mimeType)
-    , url(move(u))
+FileInfo::FileInfo(FileSourceInfo sourceInfo, qint64 payloadSize,
+                   const QMimeType& mimeType, QString originalFilename)
+    : source(move(sourceInfo))
+    , mimeType(mimeType)
     , payloadSize(payloadSize)
     , originalName(move(originalFilename))
-    , file(file)
 {
     if (!isValid())
         qCWarning(MESSAGES)
@@ -43,77 +42,81 @@ FileInfo::FileInfo(QUrl u, qint64 payloadSize, const QMimeType& mimeType,
                "0.7; for local resources, use FileInfo(QFileInfo) instead";
 }
 
-FileInfo::FileInfo(QUrl mxcUrl, const QJsonObject& infoJson,
-                   const Omittable<EncryptedFile> &file,
+FileInfo::FileInfo(FileSourceInfo sourceInfo, const QJsonObject& infoJson,
                    QString originalFilename)
-    : originalInfoJson(infoJson)
+    : source(move(sourceInfo))
+    , originalInfoJson(infoJson)
     , mimeType(
           QMimeDatabase().mimeTypeForName(infoJson["mimetype"_ls].toString()))
-    , url(move(mxcUrl))
     , payloadSize(fromJson<qint64>(infoJson["size"_ls]))
     , originalName(move(originalFilename))
-    , file(file)
 {
-    if(url.isEmpty() && file.has_value()) {
-        url = file->url;
-    }
     if (!mimeType.isValid())
         mimeType = QMimeDatabase().mimeTypeForData(QByteArray());
 }
 
 bool FileInfo::isValid() const
 {
-    return url.scheme() == "mxc"
-           && (url.authority() + url.path()).count('/') == 1;
+    const auto& u = url();
+    return u.scheme() == "mxc" && (u.authority() + u.path()).count('/') == 1;
 }
 
-void FileInfo::fillInfoJson(QJsonObject* infoJson) const
+QUrl FileInfo::url() const
 {
-    Q_ASSERT(infoJson);
-    if (payloadSize != -1)
-        infoJson->insert(QStringLiteral("size"), payloadSize);
-    if (mimeType.isValid())
-        infoJson->insert(QStringLiteral("mimetype"), mimeType.name());
-    //TODO add encryptedfile
+    return getUrlFromSourceInfo(source);
+}
+
+QJsonObject Quotient::EventContent::toInfoJson(const FileInfo& info)
+{
+    QJsonObject infoJson;
+    if (info.payloadSize != -1)
+        infoJson.insert(QStringLiteral("size"), info.payloadSize);
+    if (info.mimeType.isValid())
+        infoJson.insert(QStringLiteral("mimetype"), info.mimeType.name());
+    return infoJson;
 }
 
 ImageInfo::ImageInfo(const QFileInfo& fi, QSize imageSize)
     : FileInfo(fi), imageSize(imageSize)
 {}
 
-ImageInfo::ImageInfo(const QUrl& mxcUrl, qint64 fileSize, const QMimeType& type,
-                     QSize imageSize, const Omittable<EncryptedFile> &file, const QString& originalFilename)
-    : FileInfo(mxcUrl, fileSize, type, file, originalFilename)
+ImageInfo::ImageInfo(FileSourceInfo sourceInfo, qint64 fileSize,
+                     const QMimeType& type, QSize imageSize,
+                     const QString& originalFilename)
+    : FileInfo(move(sourceInfo), fileSize, type, originalFilename)
     , imageSize(imageSize)
 {}
 
-ImageInfo::ImageInfo(const QUrl& mxcUrl, const QJsonObject& infoJson,
-                     const Omittable<EncryptedFile> &file,
+ImageInfo::ImageInfo(FileSourceInfo sourceInfo, const QJsonObject& infoJson,
                      const QString& originalFilename)
-    : FileInfo(mxcUrl, infoJson, file, originalFilename)
+    : FileInfo(move(sourceInfo), infoJson, originalFilename)
     , imageSize(infoJson["w"_ls].toInt(), infoJson["h"_ls].toInt())
 {}
 
-void ImageInfo::fillInfoJson(QJsonObject* infoJson) const
+QJsonObject Quotient::EventContent::toInfoJson(const ImageInfo& info)
 {
-    FileInfo::fillInfoJson(infoJson);
-    if (imageSize.width() != -1)
-        infoJson->insert(QStringLiteral("w"), imageSize.width());
-    if (imageSize.height() != -1)
-        infoJson->insert(QStringLiteral("h"), imageSize.height());
+    auto infoJson = toInfoJson(static_cast<const FileInfo&>(info));
+    if (info.imageSize.width() != -1)
+        infoJson.insert(QStringLiteral("w"), info.imageSize.width());
+    if (info.imageSize.height() != -1)
+        infoJson.insert(QStringLiteral("h"), info.imageSize.height());
+    return infoJson;
 }
 
-Thumbnail::Thumbnail(const QJsonObject& infoJson, const Omittable<EncryptedFile> &file)
+Thumbnail::Thumbnail(const QJsonObject& infoJson,
+                     const Omittable<EncryptedFileMetadata>& efm)
     : ImageInfo(QUrl(infoJson["thumbnail_url"_ls].toString()),
-                infoJson["thumbnail_info"_ls].toObject(),
-                file)
-{}
+                infoJson["thumbnail_info"_ls].toObject())
+{
+    if (efm)
+        source = *efm;
+}
 
-void Thumbnail::fillInfoJson(QJsonObject* infoJson) const
+void Thumbnail::dumpTo(QJsonObject& infoJson) const
 {
-    if (url.isValid())
-        infoJson->insert(QStringLiteral("thumbnail_url"), url.toString());
+    if (url().isValid())
+        fillJson(infoJson, { "thumbnail_url"_ls, "thumbnail_file"_ls }, source);
     if (!imageSize.isEmpty())
-        infoJson->insert(QStringLiteral("thumbnail_info"),
-                         toInfoJson<ImageInfo>(*this));
+        infoJson.insert(QStringLiteral("thumbnail_info"),
+                         toInfoJson(*this));
 }
diff --git a/lib/events/eventcontent.h b/lib/events/eventcontent.h
index de9a792b..af26c0a4 100644
--- a/lib/events/eventcontent.h
+++ b/lib/events/eventcontent.h
@@ -6,279 +6,249 @@
 // This file contains generic event content definitions, applicable to room
 // message events as well as other events (e.g., avatars).
 
-#include "encryptedfile.h"
+#include "filesourceinfo.h"
 #include "quotient_export.h"
 
 #include <QtCore/QJsonObject>
+#include <QtCore/QMetaType>
 #include <QtCore/QMimeType>
 #include <QtCore/QSize>
 #include <QtCore/QUrl>
-#include <QtCore/QMetaType>
 
 class QFileInfo;
 
-namespace Quotient {
-namespace EventContent {
-    /**
-     * A base class for all content types that can be stored
-     * in a RoomMessageEvent
-     *
-     * Each content type class should have a constructor taking
-     * a QJsonObject and override fillJson() with an implementation
-     * that will fill the target QJsonObject with stored values. It is
-     * assumed but not required that a content object can also be created
-     * from plain data.
-     */
-    class QUOTIENT_API Base {
-    public:
-        explicit Base(QJsonObject o = {}) : originalJson(std::move(o)) {}
-        virtual ~Base() = default;
-
-        // FIXME: make toJson() from converters.* work on base classes
-        QJsonObject toJson() const;
-
-    public:
-        QJsonObject originalJson;
-
-    protected:
-        Base(const Base&) = default;
-        Base(Base&&) = default;
-
-        virtual void fillJson(QJsonObject* o) const = 0;
-    };
-
-    // The below structures fairly follow CS spec 11.2.1.6. The overall
-    // set of attributes for each content types is a superset of the spec
-    // but specific aggregation structure is altered. See doc comments to
-    // each type for the list of available attributes.
-
-    // A quick classes inheritance structure follows (the definitions are
-    // spread across eventcontent.h and roommessageevent.h):
-    // FileInfo
-    //   FileContent : UrlWithThumbnailContent<FileInfo>
-    //   AudioContent : PlayableContent<UrlBasedContent<FileInfo>>
-    //   ImageInfo : FileInfo + imageSize attribute
-    //     ImageContent : UrlWithThumbnailContent<ImageInfo>
-    //     VideoContent : PlayableContent<UrlWithThumbnailContent<ImageInfo>>
-
-    /**
-     * A base/mixin class for structures representing an "info" object for
-     * some content types. These include most attachment types currently in
-     * the CS API spec.
-     *
-     * In order to use it in a content class, derive both from TypedBase
-     * (or Base) and from FileInfo (or its derivative, such as \p ImageInfo)
-     * and call fillInfoJson() to fill the "info" subobject. Make sure
-     * to pass an "info" part of JSON to FileInfo constructor, not the whole
-     * JSON content, as well as contents of "url" (or a similar key) and
-     * optionally "filename" node from the main JSON content. Assuming you
-     * don't do unusual things, you should use \p UrlBasedContent<> instead
-     * of doing multiple inheritance and overriding Base::fillJson() by hand.
-     *
-     * This class is not polymorphic.
-     */
-    class QUOTIENT_API FileInfo {
-    public:
-        FileInfo() = default;
-        explicit FileInfo(const QFileInfo& fi);
-        explicit FileInfo(QUrl mxcUrl, qint64 payloadSize = -1,
-                          const QMimeType& mimeType = {},
-                          Omittable<EncryptedFile> file = none,
-                          QString originalFilename = {});
-        FileInfo(QUrl mxcUrl, const QJsonObject& infoJson,
-                 const Omittable<EncryptedFile> &file,
-                 QString originalFilename = {});
-
-        bool isValid() const;
-
-        void fillInfoJson(QJsonObject* infoJson) const;
-
-        /**
-         * \brief Extract media id from the URL
-         *
-         * This can be used, e.g., to construct a QML-facing image://
-         * URI as follows:
-         * \code "image://provider/" + info.mediaId() \endcode
-         */
-        QString mediaId() const { return url.authority() + url.path(); }
-
-    public:
-        QJsonObject originalInfoJson;
-        QMimeType mimeType;
-        QUrl url;
-        qint64 payloadSize = 0;
-        QString originalName;
-        Omittable<EncryptedFile> file = none;
-    };
-
-    template <typename InfoT>
-    QJsonObject toInfoJson(const InfoT& info)
+namespace Quotient::EventContent {
+//! \brief Base for all content types that can be stored in RoomMessageEvent
+//!
+//! Each content type class should have a constructor taking
+//! a QJsonObject and override fillJson() with an implementation
+//! that will fill the target QJsonObject with stored values. It is
+//! assumed but not required that a content object can also be created
+//! from plain data.
+class QUOTIENT_API Base {
+public:
+    explicit Base(QJsonObject o = {}) : originalJson(std::move(o)) {}
+    virtual ~Base() = default;
+
+    QJsonObject toJson() const;
+
+public:
+    QJsonObject originalJson;
+
+    // You can't assign those classes
+    Base& operator=(const Base&) = delete;
+    Base& operator=(Base&&) = delete;
+
+protected:
+    Base(const Base&) = default;
+    Base(Base&&) noexcept = default;
+
+    virtual void fillJson(QJsonObject&) const = 0;
+};
+
+// The below structures fairly follow CS spec 11.2.1.6. The overall
+// set of attributes for each content types is a superset of the spec
+// but specific aggregation structure is altered. See doc comments to
+// each type for the list of available attributes.
+
+// A quick classes inheritance structure follows (the definitions are
+// spread across eventcontent.h and roommessageevent.h):
+// UrlBasedContent<InfoT> : InfoT + thumbnail data
+//   PlayableContent<InfoT> : + duration attribute
+// FileInfo
+//   FileContent = UrlBasedContent<FileInfo>
+//   AudioContent = PlayableContent<FileInfo>
+//   ImageInfo : FileInfo + imageSize attribute
+//     ImageContent = UrlBasedContent<ImageInfo>
+//     VideoContent = PlayableContent<ImageInfo>
+
+//! \brief Mix-in class representing `info` subobject in content JSON
+//!
+//! This is one of base classes for content types that deal with files or
+//! URLs. It stores the file metadata attributes, such as size, MIME type
+//! etc. found in the `content/info` subobject of event JSON payloads.
+//! Actual content classes derive from this class _and_ TypedBase that
+//! provides a polymorphic interface to access data in the mix-in. FileInfo
+//! (as well as ImageInfo, that adds image size to the metadata) is NOT
+//! polymorphic and is used in a non-polymorphic way to store thumbnail
+//! metadata (in a separate instance), next to the metadata on the file
+//! itself.
+//!
+//! If you need to make a new _content_ (not info) class based on files/URLs
+//! take UrlBasedContent as the example, i.e.:
+//! 1. Double-inherit from this class (or ImageInfo) and TypedBase.
+//! 2. Provide a constructor from QJsonObject that will pass the `info`
+//!    subobject (not the whole content JSON) down to FileInfo/ImageInfo.
+//! 3. Override fillJson() to customise the JSON export logic. Make sure
+//!    to call toInfoJson() from it to produce the payload for the `info`
+//!    subobject in the JSON payload.
+//!
+//! \sa ImageInfo, FileContent, ImageContent, AudioContent, VideoContent,
+//!     UrlBasedContent
+class QUOTIENT_API FileInfo {
+public:
+    FileInfo() = default;
+    //! \brief Construct from a QFileInfo object
+    //!
+    //! \param fi a QFileInfo object referring to an existing file
+    explicit FileInfo(const QFileInfo& fi);
+    explicit FileInfo(FileSourceInfo sourceInfo, qint64 payloadSize = -1,
+                      const QMimeType& mimeType = {},
+                      QString originalFilename = {});
+    //! \brief Construct from a JSON `info` payload
+    //!
+    //! Make sure to pass the `info` subobject of content JSON, not the
+    //! whole JSON content.
+    FileInfo(FileSourceInfo sourceInfo, const QJsonObject& infoJson,
+             QString originalFilename = {});
+
+    bool isValid() const;
+    QUrl url() const;
+
+    //! \brief Extract media id from the URL
+    //!
+    //! This can be used, e.g., to construct a QML-facing image://
+    //! URI as follows:
+    //! \code "image://provider/" + info.mediaId() \endcode
+    QString mediaId() const { return url().authority() + url().path(); }
+
+public:
+    FileSourceInfo source;
+    QJsonObject originalInfoJson;
+    QMimeType mimeType;
+    qint64 payloadSize = 0;
+    QString originalName;
+};
+
+QUOTIENT_API QJsonObject toInfoJson(const FileInfo& info);
+
+//! \brief A content info class for image/video content types and thumbnails
+class QUOTIENT_API ImageInfo : public FileInfo {
+public:
+    ImageInfo() = default;
+    explicit ImageInfo(const QFileInfo& fi, QSize imageSize = {});
+    explicit ImageInfo(FileSourceInfo sourceInfo, qint64 fileSize = -1,
+                       const QMimeType& type = {}, QSize imageSize = {},
+                       const QString& originalFilename = {});
+    ImageInfo(FileSourceInfo sourceInfo, const QJsonObject& infoJson,
+              const QString& originalFilename = {});
+
+public:
+    QSize imageSize;
+};
+
+QUOTIENT_API QJsonObject toInfoJson(const ImageInfo& info);
+
+//! \brief An auxiliary class for an info type that carries a thumbnail
+//!
+//! This class saves/loads a thumbnail to/from `info` subobject of
+//! the JSON representation of event content; namely, `info/thumbnail_url`
+//! (or, in case of an encrypted thumbnail, `info/thumbnail_file`) and
+//! `info/thumbnail_info` fields are used.
+class QUOTIENT_API Thumbnail : public ImageInfo {
+public:
+    using ImageInfo::ImageInfo;
+    explicit Thumbnail(const QJsonObject& infoJson,
+                       const Omittable<EncryptedFileMetadata>& efm = none);
+
+    //! \brief Add thumbnail information to the passed `info` JSON object
+    void dumpTo(QJsonObject& infoJson) const;
+};
+
+class QUOTIENT_API TypedBase : public Base {
+public:
+    virtual QMimeType type() const = 0;
+    virtual const FileInfo* fileInfo() const { return nullptr; }
+    virtual FileInfo* fileInfo() { return nullptr; }
+    virtual const Thumbnail* thumbnailInfo() const { return nullptr; }
+
+protected:
+    explicit TypedBase(QJsonObject o = {}) : Base(std::move(o)) {}
+    using Base::Base;
+};
+
+//! \brief A template class for content types with a URL and additional info
+//!
+//! Types that derive from this class template take `url` (or, if the file
+//! is encrypted, `file`) and, optionally, `filename` values from
+//! the top-level JSON object and the rest of information from the `info`
+//! subobject, as defined by the parameter type.
+//! \tparam InfoT base info class - FileInfo or ImageInfo
+template <class InfoT>
+class UrlBasedContent : public TypedBase, public InfoT {
+public:
+    using InfoT::InfoT;
+    explicit UrlBasedContent(const QJsonObject& json)
+        : TypedBase(json)
+        , InfoT(QUrl(json["url"].toString()), json["info"].toObject(),
+                json["filename"].toString())
+        , thumbnail(FileInfo::originalInfoJson)
     {
-        QJsonObject infoJson;
-        info.fillInfoJson(&infoJson);
-        return infoJson;
+        if (const auto efmJson = json.value("file"_ls).toObject();
+                !efmJson.isEmpty())
+            InfoT::source = fromJson<EncryptedFileMetadata>(efmJson);
+        // Two small hacks on originalJson to expose mediaIds to QML
+        originalJson.insert("mediaId", InfoT::mediaId());
+        originalJson.insert("thumbnailMediaId", thumbnail.mediaId());
     }
 
-    /**
-     * A content info class for image content types: image, thumbnail, video
-     */
-    class QUOTIENT_API ImageInfo : public FileInfo {
-    public:
-        ImageInfo() = default;
-        explicit ImageInfo(const QFileInfo& fi, QSize imageSize = {});
-        explicit ImageInfo(const QUrl& mxcUrl, qint64 fileSize = -1,
-                           const QMimeType& type = {}, QSize imageSize = {},
-                           const Omittable<EncryptedFile> &file = none,
-                           const QString& originalFilename = {});
-        ImageInfo(const QUrl& mxcUrl, const QJsonObject& infoJson,
-                  const Omittable<EncryptedFile> &encryptedFile,
-                  const QString& originalFilename = {});
-
-        void fillInfoJson(QJsonObject* infoJson) const;
-
-    public:
-        QSize imageSize;
-    };
-
-    /**
-     * An auxiliary class for an info type that carries a thumbnail
-     *
-     * This class saves/loads a thumbnail to/from "info" subobject of
-     * the JSON representation of event content; namely,
-     * "info/thumbnail_url" and "info/thumbnail_info" fields are used.
-     */
-    class QUOTIENT_API Thumbnail : public ImageInfo {
-    public:
-        using ImageInfo::ImageInfo;
-        Thumbnail(const QJsonObject& infoJson, const Omittable<EncryptedFile> &file = none);
-
-        /**
-         * Writes thumbnail information to "thumbnail_info" subobject
-         * and thumbnail URL to "thumbnail_url" node inside "info".
-         */
-        void fillInfoJson(QJsonObject* infoJson) const;
-    };
-
-    class QUOTIENT_API TypedBase : public Base {
-    public:
-        virtual QMimeType type() const = 0;
-        virtual const FileInfo* fileInfo() const { return nullptr; }
-        virtual FileInfo* fileInfo() { return nullptr; }
-        virtual const Thumbnail* thumbnailInfo() const { return nullptr; }
-
-    protected:
-        explicit TypedBase(QJsonObject o = {}) : Base(std::move(o)) {}
-        using Base::Base;
-    };
-
-    /**
-     * A base class for content types that have a URL and additional info
-     *
-     * Types that derive from this class template take "url" and,
-     * optionally, "filename" values from the top-level JSON object and
-     * the rest of information from the "info" subobject, as defined by
-     * the parameter type.
-     *
-     * \tparam InfoT base info class
-     */
-    template <class InfoT>
-    class QUOTIENT_API UrlBasedContent : public TypedBase, public InfoT {
-    public:
-        using InfoT::InfoT;
-        explicit UrlBasedContent(const QJsonObject& json)
-            : TypedBase(json)
-            , InfoT(QUrl(json["url"].toString()), json["info"].toObject(),
-                    fromJson<Omittable<EncryptedFile>>(json["file"]), json["filename"].toString())
-        {
-            // A small hack to facilitate links creation in QML.
-            originalJson.insert("mediaId", InfoT::mediaId());
-        }
-
-        QMimeType type() const override { return InfoT::mimeType; }
-        const FileInfo* fileInfo() const override { return this; }
-        FileInfo* fileInfo() override { return this; }
-
-    protected:
-        void fillJson(QJsonObject* json) const override
-        {
-            Q_ASSERT(json);
-            if (!InfoT::file.has_value()) {
-                json->insert("url", InfoT::url.toString());
-            } else {
-                json->insert("file", Quotient::toJson(*InfoT::file));
-            }
-            if (!InfoT::originalName.isEmpty())
-                json->insert("filename", InfoT::originalName);
-            json->insert("info", toInfoJson<InfoT>(*this));
-        }
-    };
-
-    template <typename InfoT>
-    class QUOTIENT_API UrlWithThumbnailContent : public UrlBasedContent<InfoT> {
-    public:
-        // NB: when using inherited constructors, thumbnail has to be
-        // initialised separately
-        using UrlBasedContent<InfoT>::UrlBasedContent;
-        explicit UrlWithThumbnailContent(const QJsonObject& json)
-            : UrlBasedContent<InfoT>(json), thumbnail(InfoT::originalInfoJson)
-        {
-            // Another small hack, to simplify making a thumbnail link
-            UrlBasedContent<InfoT>::originalJson.insert("thumbnailMediaId",
-                                                        thumbnail.mediaId());
-        }
-
-        const Thumbnail* thumbnailInfo() const override { return &thumbnail; }
-
-    public:
-        Thumbnail thumbnail;
-
-    protected:
-        void fillJson(QJsonObject* json) const override
-        {
-            UrlBasedContent<InfoT>::fillJson(json);
-            auto infoJson = json->take("info").toObject();
-            thumbnail.fillInfoJson(&infoJson);
-            json->insert("info", infoJson);
-        }
-    };
-
-    /**
-     * Content class for m.image
-     *
-     * Available fields:
-     * - corresponding to the top-level JSON:
-     *   - url
-     *   - filename (extension to the spec)
-     * - corresponding to the "info" subobject:
-     *   - payloadSize ("size" in JSON)
-     *   - mimeType ("mimetype" in JSON)
-     *   - imageSize (QSize for a combination of "h" and "w" in JSON)
-     *   - thumbnail.url ("thumbnail_url" in JSON)
-     * - corresponding to the "info/thumbnail_info" subobject: contents of
-     *   thumbnail field, in the same vein as for the main image:
-     *   - payloadSize
-     *   - mimeType
-     *   - imageSize
-     */
-    using ImageContent = UrlWithThumbnailContent<ImageInfo>;
-
-    /**
-     * Content class for m.file
-     *
-     * Available fields:
-     * - corresponding to the top-level JSON:
-     *   - url
-     *   - filename
-     * - corresponding to the "info" subobject:
-     *   - payloadSize ("size" in JSON)
-     *   - mimeType ("mimetype" in JSON)
-     *   - thumbnail.url ("thumbnail_url" in JSON)
-     * - corresponding to the "info/thumbnail_info" subobject:
-     *   - thumbnail.payloadSize
-     *   - thumbnail.mimeType
-     *   - thumbnail.imageSize (QSize for "h" and "w" in JSON)
-     */
-    using FileContent = UrlWithThumbnailContent<FileInfo>;
-} // namespace EventContent
-} // namespace Quotient
+    QMimeType type() const override { return InfoT::mimeType; }
+    const FileInfo* fileInfo() const override { return this; }
+    FileInfo* fileInfo() override { return this; }
+    const Thumbnail* thumbnailInfo() const override { return &thumbnail; }
+
+public:
+    Thumbnail thumbnail;
+
+protected:
+    virtual void fillInfoJson(QJsonObject& infoJson [[maybe_unused]]) const
+    {}
+
+    void fillJson(QJsonObject& json) const override
+    {
+        Quotient::fillJson(json, { "url"_ls, "file"_ls }, InfoT::source);
+        if (!InfoT::originalName.isEmpty())
+            json.insert("filename", InfoT::originalName);
+        auto infoJson = toInfoJson(*this);
+        if (thumbnail.isValid())
+            thumbnail.dumpTo(infoJson);
+        fillInfoJson(infoJson);
+        json.insert("info", infoJson);
+    }
+};
+
+//! \brief Content class for m.image
+//!
+//! Available fields:
+//! - corresponding to the top-level JSON:
+//!   - source (corresponding to `url` or `file` in JSON)
+//!   - filename (extension to the spec)
+//! - corresponding to the `info` subobject:
+//!   - payloadSize (`size` in JSON)
+//!   - mimeType (`mimetype` in JSON)
+//!   - imageSize (QSize for a combination of `h` and `w` in JSON)
+//!   - thumbnail.url (`thumbnail_url` in JSON)
+//! - corresponding to the `info/thumbnail_info` subobject: contents of
+//!   thumbnail field, in the same vein as for the main image:
+//!   - payloadSize
+//!   - mimeType
+//!   - imageSize
+using ImageContent = UrlBasedContent<ImageInfo>;
+
+//! \brief Content class for m.file
+//!
+//! Available fields:
+//! - corresponding to the top-level JSON:
+//!   - source (corresponding to `url` or `file` in JSON)
+//!   - filename
+//! - corresponding to the `info` subobject:
+//!   - payloadSize (`size` in JSON)
+//!   - mimeType (`mimetype` in JSON)
+//!   - thumbnail.source (`thumbnail_url` or `thumbnail_file` in JSON)
+//! - corresponding to the `info/thumbnail_info` subobject:
+//!   - thumbnail.payloadSize
+//!   - thumbnail.mimeType
+//!   - thumbnail.imageSize (QSize for `h` and `w` in JSON)
+using FileContent = UrlBasedContent<FileInfo>;
+} // namespace Quotient::EventContent
 Q_DECLARE_METATYPE(const Quotient::EventContent::TypedBase*)
diff --git a/lib/events/eventloader.h b/lib/events/eventloader.h
index fe624d70..4c639efa 100644
--- a/lib/events/eventloader.h
+++ b/lib/events/eventloader.h
@@ -19,43 +19,27 @@ inline event_ptr_tt<BaseEventT> loadEvent(const QJsonObject& fullJson)
     return doLoadEvent<BaseEventT>(fullJson, fullJson[TypeKeyL].toString());
 }
 
-/*! Create an event from a type string and content JSON
- *
- * Use this factory template to resolve the C++ type from the Matrix
- * type string in \p matrixType and create an event of that type that has
- * its content part set to \p content.
- */
-template <typename BaseEventT>
-inline event_ptr_tt<BaseEventT> loadEvent(const QString& matrixType,
-                                          const QJsonObject& content)
+//! \brief Create an event from a type string and content JSON
+//!
+//! Use this template to resolve the C++ type from the Matrix type string in
+//! \p matrixType and create an event of that type by passing all parameters
+//! to BaseEventT::basicJson().
+template <typename BaseEventT, typename... BasicJsonParamTs>
+inline event_ptr_tt<BaseEventT> loadEvent(
+    const QString& matrixType, const BasicJsonParamTs&... basicJsonParams)
 {
-    return doLoadEvent<BaseEventT>(basicEventJson(matrixType, content),
-                                   matrixType);
-}
-
-/*! Create a state event from a type string, content JSON and state key
- *
- * Use this factory to resolve the C++ type from the Matrix type string
- * in \p matrixType and create a state event of that type with content part
- * set to \p content and state key set to \p stateKey (empty by default).
- */
-inline StateEventPtr loadStateEvent(const QString& matrixType,
-                                    const QJsonObject& content,
-                                    const QString& stateKey = {})
-{
-    return doLoadEvent<StateEventBase>(
-        basicStateEventJson(matrixType, content, stateKey), matrixType);
+    return doLoadEvent<BaseEventT>(
+        BaseEventT::basicJson(matrixType, basicJsonParams...), matrixType);
 }
 
 template <typename EventT>
-struct JsonConverter<event_ptr_tt<EventT>> {
-    static auto load(const QJsonValue& jv)
+struct JsonConverter<event_ptr_tt<EventT>>
+    : JsonObjectUnpacker<event_ptr_tt<EventT>> {
+    using JsonObjectUnpacker<event_ptr_tt<EventT>>::load;
+    static auto load(const QJsonObject& jo)
     {
-        return loadEvent<EventT>(jv.toObject());
-    }
-    static auto load(const QJsonDocument& jd)
-    {
-        return loadEvent<EventT>(jd.object());
+        return loadEvent<EventT>(jo);
     }
 };
+
 } // namespace Quotient
diff --git a/lib/events/eventrelation.h b/lib/events/eventrelation.h
index e445ee42..2a841cf1 100644
--- a/lib/events/eventrelation.h
+++ b/lib/events/eventrelation.h
@@ -34,11 +34,11 @@ struct QUOTIENT_API EventRelation {
         return { ReplacementType, std::move(eventId) };
     }
 
-    [[deprecated("Use ReplyRelation variable instead")]]
+    [[deprecated("Use ReplyType variable instead")]]
     static constexpr auto Reply() { return ReplyType; }
-    [[deprecated("Use AnnotationRelation variable instead")]] //
+    [[deprecated("Use AnnotationType variable instead")]] //
     static constexpr auto Annotation() { return AnnotationType; }
-    [[deprecated("Use ReplacementRelation variable instead")]] //
+    [[deprecated("Use ReplacementType variable instead")]] //
     static constexpr auto Replacement() { return ReplacementType; }
 };
 
diff --git a/lib/events/filesourceinfo.cpp b/lib/events/filesourceinfo.cpp
new file mode 100644
index 00000000..e8b6794b
--- /dev/null
+++ b/lib/events/filesourceinfo.cpp
@@ -0,0 +1,172 @@
+// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "filesourceinfo.h"
+
+#include "logging.h"
+#include "util.h"
+
+#ifdef Quotient_E2EE_ENABLED
+#    include "e2ee/qolmutils.h"
+
+#    include <QtCore/QCryptographicHash>
+
+#    include <openssl/evp.h>
+#endif
+
+using namespace Quotient;
+
+QByteArray Quotient::decryptFile(const QByteArray& ciphertext,
+                                 const EncryptedFileMetadata& metadata)
+{
+#ifdef Quotient_E2EE_ENABLED
+    if (QByteArray::fromBase64(metadata.hashes["sha256"_ls].toLatin1())
+        != QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
+        qCWarning(E2EE) << "Hash verification failed for file";
+        return {};
+    }
+
+    auto _key = metadata.key.k;
+    const auto keyBytes = QByteArray::fromBase64(
+        _key.replace(u'_', u'/').replace(u'-', u'+').toLatin1());
+    int length;
+    auto* ctx = EVP_CIPHER_CTX_new();
+    QByteArray plaintext(ciphertext.size() + EVP_MAX_BLOCK_LENGTH - 1, '\0');
+    EVP_DecryptInit_ex(
+        ctx, EVP_aes_256_ctr(), nullptr,
+        reinterpret_cast<const unsigned char*>(keyBytes.data()),
+        reinterpret_cast<const unsigned char*>(
+            QByteArray::fromBase64(metadata.iv.toLatin1()).data()));
+    EVP_DecryptUpdate(ctx, reinterpret_cast<unsigned char*>(plaintext.data()),
+                      &length,
+                      reinterpret_cast<const unsigned char*>(ciphertext.data()),
+                      ciphertext.size());
+    EVP_DecryptFinal_ex(ctx,
+                        reinterpret_cast<unsigned char*>(plaintext.data())
+                            + length,
+                        &length);
+    EVP_CIPHER_CTX_free(ctx);
+    return plaintext.left(ciphertext.size());
+#else
+    qWarning(MAIN) << "This build of libQuotient doesn't support E2EE, "
+                      "cannot decrypt the file";
+    return ciphertext;
+#endif
+}
+
+std::pair<EncryptedFileMetadata, QByteArray> Quotient::encryptFile(
+    const QByteArray& plainText)
+{
+#ifdef Quotient_E2EE_ENABLED
+    QByteArray k = getRandom(32);
+    auto kBase64 = k.toBase64();
+    QByteArray iv = getRandom(16);
+    JWK key = { "oct"_ls,
+                { "encrypt"_ls, "decrypt"_ls },
+                "A256CTR"_ls,
+                QString(k.toBase64())
+                    .replace(u'/', u'_')
+                    .replace(u'+', u'-')
+                    .left(kBase64.indexOf('=')),
+                true };
+
+    int length;
+    auto* ctx = EVP_CIPHER_CTX_new();
+    EVP_EncryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr,
+                       reinterpret_cast<const unsigned char*>(k.data()),
+                       reinterpret_cast<const unsigned char*>(iv.data()));
+    const auto blockSize = EVP_CIPHER_CTX_block_size(ctx);
+    QByteArray cipherText(plainText.size() + blockSize - 1, '\0');
+    EVP_EncryptUpdate(ctx, reinterpret_cast<unsigned char*>(cipherText.data()),
+                      &length,
+                      reinterpret_cast<const unsigned char*>(plainText.data()),
+                      plainText.size());
+    EVP_EncryptFinal_ex(ctx,
+                        reinterpret_cast<unsigned char*>(cipherText.data())
+                            + length,
+                        &length);
+    EVP_CIPHER_CTX_free(ctx);
+
+    auto hash = QCryptographicHash::hash(cipherText, QCryptographicHash::Sha256)
+                    .toBase64();
+    auto ivBase64 = iv.toBase64();
+    EncryptedFileMetadata efm = { {},
+                           key,
+                           ivBase64.left(ivBase64.indexOf('=')),
+                           { { QStringLiteral("sha256"),
+                               hash.left(hash.indexOf('=')) } },
+                           "v2"_ls };
+    return { efm, cipherText };
+#else
+    return {};
+#endif
+}
+
+void JsonObjectConverter<EncryptedFileMetadata>::dumpTo(QJsonObject& jo,
+                                                const EncryptedFileMetadata& pod)
+{
+    addParam<>(jo, QStringLiteral("url"), pod.url);
+    addParam<>(jo, QStringLiteral("key"), pod.key);
+    addParam<>(jo, QStringLiteral("iv"), pod.iv);
+    addParam<>(jo, QStringLiteral("hashes"), pod.hashes);
+    addParam<>(jo, QStringLiteral("v"), pod.v);
+}
+
+void JsonObjectConverter<EncryptedFileMetadata>::fillFrom(const QJsonObject& jo,
+                                                  EncryptedFileMetadata& pod)
+{
+    fromJson(jo.value("url"_ls), pod.url);
+    fromJson(jo.value("key"_ls), pod.key);
+    fromJson(jo.value("iv"_ls), pod.iv);
+    fromJson(jo.value("hashes"_ls), pod.hashes);
+    fromJson(jo.value("v"_ls), pod.v);
+}
+
+void JsonObjectConverter<JWK>::dumpTo(QJsonObject& jo, const JWK& pod)
+{
+    addParam<>(jo, QStringLiteral("kty"), pod.kty);
+    addParam<>(jo, QStringLiteral("key_ops"), pod.keyOps);
+    addParam<>(jo, QStringLiteral("alg"), pod.alg);
+    addParam<>(jo, QStringLiteral("k"), pod.k);
+    addParam<>(jo, QStringLiteral("ext"), pod.ext);
+}
+
+void JsonObjectConverter<JWK>::fillFrom(const QJsonObject& jo, JWK& pod)
+{
+    fromJson(jo.value("kty"_ls), pod.kty);
+    fromJson(jo.value("key_ops"_ls), pod.keyOps);
+    fromJson(jo.value("alg"_ls), pod.alg);
+    fromJson(jo.value("k"_ls), pod.k);
+    fromJson(jo.value("ext"_ls), pod.ext);
+}
+
+QUrl Quotient::getUrlFromSourceInfo(const FileSourceInfo& fsi)
+{
+    return std::visit(Overloads { [](const QUrl& url) { return url; },
+                                  [](const EncryptedFileMetadata& efm) {
+                                      return efm.url;
+                                  } },
+                      fsi);
+}
+
+void Quotient::setUrlInSourceInfo(FileSourceInfo& fsi, const QUrl& newUrl)
+{
+    std::visit(Overloads { [&newUrl](QUrl& url) { url = newUrl; },
+                           [&newUrl](EncryptedFileMetadata& efm) {
+                               efm.url = newUrl;
+                           } },
+               fsi);
+}
+
+void Quotient::fillJson(QJsonObject& jo,
+                        const std::array<QLatin1String, 2>& jsonKeys,
+                        const FileSourceInfo& fsi)
+{
+    // NB: Keeping variant_size_v out of the function signature for readability.
+    // NB2: Can't use jsonKeys directly inside static_assert as its value is
+    // unknown so the compiler cannot ensure size() is constexpr (go figure...)
+    static_assert(
+        std::variant_size_v<FileSourceInfo> == decltype(jsonKeys) {}.size());
+    jo.insert(jsonKeys[fsi.index()], toJson(fsi));
+}
diff --git a/lib/events/filesourceinfo.h b/lib/events/filesourceinfo.h
new file mode 100644
index 00000000..8f7e3cbe
--- /dev/null
+++ b/lib/events/filesourceinfo.h
@@ -0,0 +1,90 @@
+// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+#include "converters.h"
+
+#include <array>
+
+namespace Quotient {
+/**
+ * JSON Web Key object as specified in
+ * https://spec.matrix.org/unstable/client-server-api/#extensions-to-mroommessage-msgtypes
+ * The only currently relevant member is `k`, the rest needs to be set to the defaults specified in the spec.
+ */
+struct JWK
+{
+    Q_GADGET
+    Q_PROPERTY(QString kty MEMBER kty CONSTANT)
+    Q_PROPERTY(QStringList keyOps MEMBER keyOps CONSTANT)
+    Q_PROPERTY(QString alg MEMBER alg CONSTANT)
+    Q_PROPERTY(QString k MEMBER k CONSTANT)
+    Q_PROPERTY(bool ext MEMBER ext CONSTANT)
+
+public:
+    QString kty;
+    QStringList keyOps;
+    QString alg;
+    QString k;
+    bool ext;
+};
+
+struct QUOTIENT_API EncryptedFileMetadata {
+    Q_GADGET
+    Q_PROPERTY(QUrl url MEMBER url CONSTANT)
+    Q_PROPERTY(JWK key MEMBER key CONSTANT)
+    Q_PROPERTY(QString iv MEMBER iv CONSTANT)
+    Q_PROPERTY(QHash<QString, QString> hashes MEMBER hashes CONSTANT)
+    Q_PROPERTY(QString v MEMBER v CONSTANT)
+
+public:
+    QUrl url;
+    JWK key;
+    QString iv;
+    QHash<QString, QString> hashes;
+    QString v;
+};
+
+QUOTIENT_API std::pair<EncryptedFileMetadata, QByteArray> encryptFile(
+    const QByteArray& plainText);
+QUOTIENT_API QByteArray decryptFile(const QByteArray& ciphertext,
+                                    const EncryptedFileMetadata& metadata);
+
+template <>
+struct QUOTIENT_API JsonObjectConverter<EncryptedFileMetadata> {
+    static void dumpTo(QJsonObject& jo, const EncryptedFileMetadata& pod);
+    static void fillFrom(const QJsonObject& jo, EncryptedFileMetadata& pod);
+};
+
+template <>
+struct QUOTIENT_API JsonObjectConverter<JWK> {
+    static void dumpTo(QJsonObject& jo, const JWK& pod);
+    static void fillFrom(const QJsonObject& jo, JWK& pod);
+};
+
+using FileSourceInfo = std::variant<QUrl, EncryptedFileMetadata>;
+
+QUOTIENT_API QUrl getUrlFromSourceInfo(const FileSourceInfo& fsi);
+
+QUOTIENT_API void setUrlInSourceInfo(FileSourceInfo& fsi, const QUrl& newUrl);
+
+// The way FileSourceInfo is stored in JSON requires an extra parameter so
+// the original template is not applicable
+template <>
+void fillJson(QJsonObject&, const FileSourceInfo&) = delete;
+
+//! \brief Export FileSourceInfo to a JSON object
+//!
+//! Depending on what is stored inside FileSourceInfo, this function will insert
+//! - a key-to-string pair where key is taken from jsonKeys[0] and the string
+//!   is the URL, if FileSourceInfo stores a QUrl;
+//! - a key-to-object mapping where key is taken from jsonKeys[1] and the object
+//!   is the result of converting EncryptedFileMetadata to JSON,
+//!   if FileSourceInfo stores EncryptedFileMetadata
+QUOTIENT_API void fillJson(QJsonObject& jo,
+                           const std::array<QLatin1String, 2>& jsonKeys,
+                           const FileSourceInfo& fsi);
+
+} // namespace Quotient
diff --git a/lib/events/keyverificationevent.cpp b/lib/events/keyverificationevent.cpp
deleted file mode 100644
index e7f5b019..00000000
--- a/lib/events/keyverificationevent.cpp
+++ /dev/null
@@ -1,194 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
-// SPDX-License-Identifier: LGPL-2.1-or-later
-
-#include "keyverificationevent.h"
-
-using namespace Quotient;
-
-KeyVerificationRequestEvent::KeyVerificationRequestEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationRequestEvent::fromDevice() const
-{
-    return contentPart<QString>("from_device"_ls);
-}
-
-QString KeyVerificationRequestEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QStringList KeyVerificationRequestEvent::methods() const
-{
-    return contentPart<QStringList>("methods"_ls);
-}
-
-uint64_t KeyVerificationRequestEvent::timestamp() const
-{
-    return contentPart<double>("timestamp"_ls);
-}
-
-KeyVerificationStartEvent::KeyVerificationStartEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationStartEvent::fromDevice() const
-{
-    return contentPart<QString>("from_device"_ls);
-}
-
-QString KeyVerificationStartEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QString KeyVerificationStartEvent::method() const
-{
-    return contentPart<QString>("method"_ls);
-}
-
-Omittable<QString> KeyVerificationStartEvent::nextMethod() const
-{
-    return contentPart<Omittable<QString>>("method_ls");
-}
-
-QStringList KeyVerificationStartEvent::keyAgreementProtocols() const
-{
-    Q_ASSERT(method() == QStringLiteral("m.sas.v1"));
-    return contentPart<QStringList>("key_agreement_protocols"_ls);
-}
-
-QStringList KeyVerificationStartEvent::hashes() const
-{
-    Q_ASSERT(method() == QStringLiteral("m.sas.v1"));
-        return contentPart<QStringList>("hashes"_ls);
-
-}
-
-QStringList KeyVerificationStartEvent::messageAuthenticationCodes() const
-{
-    Q_ASSERT(method() == QStringLiteral("m.sas.v1"));
-    return contentPart<QStringList>("message_authentication_codes"_ls);
-}
-
-QString KeyVerificationStartEvent::shortAuthenticationString() const
-{
-    return contentPart<QString>("short_authentification_string"_ls);
-}
-
-KeyVerificationAcceptEvent::KeyVerificationAcceptEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationAcceptEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QString KeyVerificationAcceptEvent::method() const
-{
-    return contentPart<QString>("method"_ls);
-}
-
-QString KeyVerificationAcceptEvent::keyAgreementProtocol() const
-{
-    return contentPart<QString>("key_agreement_protocol"_ls);
-}
-
-QString KeyVerificationAcceptEvent::hashData() const
-{
-    return contentPart<QString>("hash"_ls);
-}
-
-QStringList KeyVerificationAcceptEvent::shortAuthenticationString() const
-{
-    return contentPart<QStringList>("short_authentification_string"_ls);
-}
-
-QString KeyVerificationAcceptEvent::commitment() const
-{
-    return contentPart<QString>("commitment"_ls);
-}
-
-KeyVerificationCancelEvent::KeyVerificationCancelEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationCancelEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QString KeyVerificationCancelEvent::reason() const
-{
-    return contentPart<QString>("reason"_ls);
-}
-
-QString KeyVerificationCancelEvent::code() const
-{
-    return contentPart<QString>("code"_ls);
-}
-
-KeyVerificationKeyEvent::KeyVerificationKeyEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationKeyEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QString KeyVerificationKeyEvent::key() const
-{
-    return contentPart<QString>("key"_ls);
-}
-
-KeyVerificationMacEvent::KeyVerificationMacEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationMacEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QString KeyVerificationMacEvent::keys() const
-{
-    return contentPart<QString>("keys"_ls);
-}
-
-QHash<QString, QString> KeyVerificationMacEvent::mac() const
-{
-    return contentPart<QHash<QString, QString>>("mac"_ls);
-}
-
-KeyVerificationDoneEvent::KeyVerificationDoneEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{
-}
-
-QString KeyVerificationDoneEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-
-KeyVerificationReadyEvent::KeyVerificationReadyEvent(const QJsonObject &obj)
-    : Event(typeId(), obj)
-{}
-
-QString KeyVerificationReadyEvent::fromDevice() const
-{
-    return contentPart<QString>("from_device"_ls);
-}
-
-QString KeyVerificationReadyEvent::transactionId() const
-{
-    return contentPart<QString>("transaction_id"_ls);
-}
-
-QStringList KeyVerificationReadyEvent::methods() const
-{
-    return contentPart<QStringList>("methods"_ls);
-}
diff --git a/lib/events/keyverificationevent.h b/lib/events/keyverificationevent.h
index a9f63968..cdbd5d74 100644
--- a/lib/events/keyverificationevent.h
+++ b/lib/events/keyverificationevent.h
@@ -7,29 +7,33 @@
 
 namespace Quotient {
 
+static constexpr auto SasV1Method = "m.sas.v1"_ls;
+
 /// Requests a key verification with another user's devices.
 /// Typically sent as a to-device event.
 class QUOTIENT_API KeyVerificationRequestEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.request", KeyVerificationRequestEvent)
 
-    explicit KeyVerificationRequestEvent(const QJsonObject& obj);
+    explicit KeyVerificationRequestEvent(const QJsonObject& obj)
+        : Event(TypeId, obj)
+    {}
 
     /// The device ID which is initiating the request.
-    QString fromDevice() const;
+    QUO_CONTENT_GETTER(QString, fromDevice)
 
     /// An opaque identifier for the verification request. Must
     /// be unique with respect to the devices involved.
-    QString transactionId() const;
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// The verification methods supported by the sender.
-    QStringList methods() const;
+    QUO_CONTENT_GETTER(QStringList, methods)
 
     /// The POSIX timestamp in milliseconds for when the request was
     /// made. If the request is in the future by more than 5 minutes or
     /// more than 10 minutes in the past, the message should be ignored
     /// by the receiver.
-    uint64_t timestamp() const;
+    QUO_CONTENT_GETTER(QDateTime, timestamp)
 };
 REGISTER_EVENT_TYPE(KeyVerificationRequestEvent)
 
@@ -37,16 +41,18 @@ class QUOTIENT_API KeyVerificationReadyEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.ready", KeyVerificationReadyEvent)
 
-    explicit KeyVerificationReadyEvent(const QJsonObject& obj);
+    explicit KeyVerificationReadyEvent(const QJsonObject& obj)
+        : Event(TypeId, obj)
+    {}
 
     /// The device ID which is accepting the request.
-    QString fromDevice() const;
+    QUO_CONTENT_GETTER(QString, fromDevice)
 
     /// The transaction id of the verification request
-    QString transactionId() const;
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// The verification methods supported by the sender.
-    QStringList methods() const;
+    QUO_CONTENT_GETTER(QStringList, methods)
 };
 REGISTER_EVENT_TYPE(KeyVerificationReadyEvent)
 
@@ -56,39 +62,57 @@ class QUOTIENT_API KeyVerificationStartEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.start", KeyVerificationStartEvent)
 
-    explicit KeyVerificationStartEvent(const QJsonObject &obj);
+    explicit KeyVerificationStartEvent(const QJsonObject &obj)
+        : Event(TypeId, obj)
+    {}
 
     /// The device ID which is initiating the process.
-    QString fromDevice() const;
+    QUO_CONTENT_GETTER(QString, fromDevice)
 
     /// An opaque identifier for the verification request. Must
     /// be unique with respect to the devices involved.
-    QString transactionId() const;
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// The verification method to use.
-    QString method() const;
+    QUO_CONTENT_GETTER(QString, method)
 
     /// Optional method to use to verify the other user's key with.
-    Omittable<QString> nextMethod() const;
+    QUO_CONTENT_GETTER(Omittable<QString>, nextMethod)
 
     // SAS.V1 methods
 
     /// The key agreement protocols the sending device understands.
     /// \note Only exist if method is m.sas.v1
-    QStringList keyAgreementProtocols() const;
+    QStringList keyAgreementProtocols() const
+    {
+        Q_ASSERT(method() == SasV1Method);
+        return contentPart<QStringList>("key_agreement_protocols"_ls);
+    }
 
     /// The hash methods the sending device understands.
     /// \note Only exist if method is m.sas.v1
-    QStringList hashes() const;
+    QStringList hashes() const
+    {
+        Q_ASSERT(method() == SasV1Method);
+        return contentPart<QStringList>("hashes"_ls);
+    }
 
     /// The message authentication codes that the sending device understands.
     /// \note Only exist if method is m.sas.v1
-    QStringList messageAuthenticationCodes() const;
+    QStringList messageAuthenticationCodes() const
+    {
+        Q_ASSERT(method() == SasV1Method);
+        return contentPart<QStringList>("message_authentication_codes"_ls);
+    }
 
     /// The SAS methods the sending device (and the sending device's
     /// user) understands.
     /// \note Only exist if method is m.sas.v1
-    QString shortAuthenticationString() const;
+    QString shortAuthenticationString() const
+    {
+        Q_ASSERT(method() == SasV1Method);
+        return contentPart<QString>("short_authentification_string"_ls);
+    }
 };
 REGISTER_EVENT_TYPE(KeyVerificationStartEvent)
 
@@ -98,33 +122,38 @@ class QUOTIENT_API KeyVerificationAcceptEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.accept", KeyVerificationAcceptEvent)
 
-    explicit KeyVerificationAcceptEvent(const QJsonObject& obj);
+    explicit KeyVerificationAcceptEvent(const QJsonObject& obj)
+        : Event(TypeId, obj)
+    {}
 
     /// An opaque identifier for the verification process.
-    QString transactionId() const;
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// The verification method to use. Must be 'm.sas.v1'.
-    QString method() const;
+    QUO_CONTENT_GETTER(QString, method)
 
     /// The key agreement protocol the device is choosing to use, out of
     /// the options in the m.key.verification.start message.
-    QString keyAgreementProtocol() const;
+    QUO_CONTENT_GETTER(QString, keyAgreementProtocol)
 
     /// The hash method the device is choosing to use, out of the
     /// options in the m.key.verification.start message.
-    QString hashData() const;
+    QString hashData() const
+    {
+        return contentPart<QString>("hash"_ls);
+    }
 
     /// The message authentication code the device is choosing to use, out
     /// of the options in the m.key.verification.start message.
-    QString messageAuthenticationCode() const;
+    QUO_CONTENT_GETTER(QString, messageAuthenticationCode)
 
     /// The SAS methods both devices involved in the verification process understand.
-    QStringList shortAuthenticationString() const;
+    QUO_CONTENT_GETTER(QStringList, shortAuthenticationString)
 
     /// The hash (encoded as unpadded base64) of the concatenation of the
     /// device's ephemeral public key (encoded as unpadded base64) and the
     /// canonical JSON representation of the m.key.verification.start message.
-    QString commitment() const;
+    QUO_CONTENT_GETTER(QString, commitment)
 };
 REGISTER_EVENT_TYPE(KeyVerificationAcceptEvent)
 
@@ -132,17 +161,19 @@ class QUOTIENT_API KeyVerificationCancelEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.cancel", KeyVerificationCancelEvent)
 
-    explicit KeyVerificationCancelEvent(const QJsonObject &obj);
+    explicit KeyVerificationCancelEvent(const QJsonObject &obj)
+        : Event(TypeId, obj)
+    {}
 
     /// An opaque identifier for the verification process.
-    QString transactionId() const;
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// A human readable description of the code. The client should only
     /// rely on this string if it does not understand the code.
-    QString reason() const;
+    QUO_CONTENT_GETTER(QString, reason)
 
     /// The error code for why the process/request was cancelled by the user.
-    QString code() const;
+    QUO_CONTENT_GETTER(QString, code)
 };
 REGISTER_EVENT_TYPE(KeyVerificationCancelEvent)
 
@@ -152,13 +183,15 @@ class QUOTIENT_API KeyVerificationKeyEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.key", KeyVerificationKeyEvent)
 
-    explicit KeyVerificationKeyEvent(const QJsonObject &obj);
+    explicit KeyVerificationKeyEvent(const QJsonObject &obj)
+        : Event(TypeId, obj)
+    {}
 
-    /// An opaque identifier for the verification process. 
-    QString transactionId() const;
+    /// An opaque identifier for the verification process.
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// The device's ephemeral public key, encoded as unpadded base64.
-    QString key() const;
+    QUO_CONTENT_GETTER(QString, key)
 };
 REGISTER_EVENT_TYPE(KeyVerificationKeyEvent)
 
@@ -167,15 +200,20 @@ class QUOTIENT_API KeyVerificationMacEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.mac", KeyVerificationMacEvent)
 
-    explicit KeyVerificationMacEvent(const QJsonObject &obj);
+    explicit KeyVerificationMacEvent(const QJsonObject &obj)
+        : Event(TypeId, obj)
+    {}
 
-    /// An opaque identifier for the verification process. 
-    QString transactionId() const;
+    /// An opaque identifier for the verification process.
+    QUO_CONTENT_GETTER(QString, transactionId)
 
     /// The device's ephemeral public key, encoded as unpadded base64.
-    QString keys() const;
+    QUO_CONTENT_GETTER(QString, keys)
 
-    QHash<QString, QString> mac() const;
+    QHash<QString, QString> mac() const
+    {
+        return contentPart<QHash<QString, QString>>("mac"_ls);
+    }
 };
 REGISTER_EVENT_TYPE(KeyVerificationMacEvent)
 
@@ -183,10 +221,12 @@ class QUOTIENT_API KeyVerificationDoneEvent : public Event {
 public:
     DEFINE_EVENT_TYPEID("m.key.verification.done", KeyVerificationRequestEvent)
 
-    explicit KeyVerificationDoneEvent(const QJsonObject& obj);
+    explicit KeyVerificationDoneEvent(const QJsonObject& obj)
+        : Event(TypeId, obj)
+    {}
 
     /// The same transactionId as before
-    QString transactionId() const;
+    QUO_CONTENT_GETTER(QString, transactionId)
 };
 REGISTER_EVENT_TYPE(KeyVerificationDoneEvent)
 
diff --git a/lib/events/redactionevent.h b/lib/events/redactionevent.h
index be20bf52..63617e54 100644
--- a/lib/events/redactionevent.h
+++ b/lib/events/redactionevent.h
@@ -6,7 +6,7 @@
 #include "roomevent.h"
 
 namespace Quotient {
-class RedactionEvent : public RoomEvent {
+class QUOTIENT_API RedactionEvent : public RoomEvent {
 public:
     DEFINE_EVENT_TYPEID("m.room.redaction", RedactionEvent)
 
@@ -17,7 +17,7 @@ public:
     {
         return fullJson()["redacts"_ls].toString();
     }
-    QString reason() const { return contentPart<QString>("reason"_ls); }
+    QUO_CONTENT_GETTER(QString, reason)
 };
 REGISTER_EVENT_TYPE(RedactionEvent)
 } // namespace Quotient
diff --git a/lib/events/roomavatarevent.h b/lib/events/roomavatarevent.h
index c54b5801..af291696 100644
--- a/lib/events/roomavatarevent.h
+++ b/lib/events/roomavatarevent.h
@@ -26,10 +26,10 @@ public:
                              const QSize& imageSize = {},
                              const QString& originalFilename = {})
         : RoomAvatarEvent(EventContent::ImageContent {
-            mxcUrl, fileSize, mimeType, imageSize, none, originalFilename })
+            mxcUrl, fileSize, mimeType, imageSize, originalFilename })
     {}
 
-    QUrl url() const { return content().url; }
+    QUrl url() const { return content().url(); }
 };
 REGISTER_EVENT_TYPE(RoomAvatarEvent)
 } // namespace Quotient
diff --git a/lib/events/roomcanonicalaliasevent.h b/lib/events/roomcanonicalaliasevent.h
index bb8654e5..60ca68ac 100644
--- a/lib/events/roomcanonicalaliasevent.h
+++ b/lib/events/roomcanonicalaliasevent.h
@@ -7,36 +7,31 @@
 #include "stateevent.h"
 
 namespace Quotient {
-namespace EventContent{
-    class AliasesEventContent {
-
-    public:
-
-        template<typename T1, typename T2>
-        AliasesEventContent(T1&& canonicalAlias, T2&& altAliases)
-            : canonicalAlias(std::forward<T1>(canonicalAlias))
-            , altAliases(std::forward<T2>(altAliases))
-        { }
-
-        AliasesEventContent(const QJsonObject& json)
-            : canonicalAlias(fromJson<QString>(json["alias"]))
-            , altAliases(fromJson<QStringList>(json["alt_aliases"]))
-        { }
-
-        auto toJson() const
-        {
-            QJsonObject jo;
-            addParam<IfNotEmpty>(jo, QStringLiteral("alias"), canonicalAlias);
-            addParam<IfNotEmpty>(jo, QStringLiteral("alt_aliases"), altAliases);
-            return jo;
-        }
-
+namespace EventContent {
+    struct AliasesEventContent {
         QString canonicalAlias;
         QStringList altAliases;
     };
 } // namespace EventContent
 
-class RoomCanonicalAliasEvent
+template<>
+inline EventContent::AliasesEventContent fromJson(const QJsonObject& jo)
+{
+    return EventContent::AliasesEventContent {
+        fromJson<QString>(jo["alias"_ls]),
+        fromJson<QStringList>(jo["alt_aliases"_ls])
+    };
+}
+template<>
+inline auto toJson(const EventContent::AliasesEventContent& c)
+{
+    QJsonObject jo;
+    addParam<IfNotEmpty>(jo, QStringLiteral("alias"), c.canonicalAlias);
+    addParam<IfNotEmpty>(jo, QStringLiteral("alt_aliases"), c.altAliases);
+    return jo;
+}
+
+class QUOTIENT_API RoomCanonicalAliasEvent
     : public StateEvent<EventContent::AliasesEventContent> {
 public:
     DEFINE_EVENT_TYPEID("m.room.canonical_alias", RoomCanonicalAliasEvent)
diff --git a/lib/events/roomcreateevent.cpp b/lib/events/roomcreateevent.cpp
index bb6de648..3b5024d5 100644
--- a/lib/events/roomcreateevent.cpp
+++ b/lib/events/roomcreateevent.cpp
@@ -6,20 +6,11 @@
 using namespace Quotient;
 
 template <>
-struct Quotient::JsonConverter<RoomType> {
-    static RoomType load(const QJsonValue& jv)
-    {
-        const auto& roomTypeString = jv.toString();
-        for (auto it = RoomTypeStrings.begin(); it != RoomTypeStrings.end();
-             ++it)
-            if (roomTypeString == *it)
-                return RoomType(it - RoomTypeStrings.begin());
-
-        if (!roomTypeString.isEmpty())
-            qCWarning(EVENTS) << "Unknown Room Type: " << roomTypeString;
-        return RoomType::Undefined;
-    }
-};
+RoomType Quotient::fromJson(const QJsonValue& jv)
+{
+    return enumFromJsonString(jv.toString(), RoomTypeStrings,
+                              RoomType::Undefined);
+}
 
 bool RoomCreateEvent::isFederated() const
 {
diff --git a/lib/events/roomevent.cpp b/lib/events/roomevent.cpp
index 2f482871..e695e0ec 100644
--- a/lib/events/roomevent.cpp
+++ b/lib/events/roomevent.cpp
@@ -15,9 +15,9 @@ RoomEvent::RoomEvent(Type type, event_mtype_t matrixType,
 
 RoomEvent::RoomEvent(Type type, const QJsonObject& json) : Event(type, json)
 {
-    if (const auto redaction = unsignedPart(RedactedCauseKeyL);
-        redaction.isObject())
-        _redactedBecause = makeEvent<RedactionEvent>(redaction.toObject());
+    if (const auto redaction = unsignedPart<QJsonObject>(RedactedCauseKeyL);
+        !redaction.isEmpty())
+        _redactedBecause = makeEvent<RedactionEvent>(redaction);
 }
 
 RoomEvent::~RoomEvent() = default; // Let the smart pointer do its job
@@ -101,22 +101,22 @@ void RoomEvent::dumpTo(QDebug dbg) const
     dbg << " (made at " << originTimestamp().toString(Qt::ISODate) << ')';
 }
 
-QJsonObject makeCallContentJson(const QString& callId, int version,
-                                QJsonObject content)
+QJsonObject CallEventBase::basicJson(const QString& matrixType,
+                                     const QString& callId, int version,
+                                     QJsonObject contentJson)
 {
-    content.insert(QStringLiteral("call_id"), callId);
-    content.insert(QStringLiteral("version"), version);
-    return content;
+    contentJson.insert(QStringLiteral("call_id"), callId);
+    contentJson.insert(QStringLiteral("version"), version);
+    return RoomEvent::basicJson(matrixType, contentJson);
 }
 
 CallEventBase::CallEventBase(Type type, event_mtype_t matrixType,
                              const QString& callId, int version,
                              const QJsonObject& contentJson)
-    : RoomEvent(type, matrixType,
-                makeCallContentJson(callId, version, contentJson))
+    : RoomEvent(type, basicJson(matrixType, callId, version, contentJson))
 {}
 
-CallEventBase::CallEventBase(Event::Type type, const QJsonObject& json)
+CallEventBase::CallEventBase(Type type, const QJsonObject& json)
     : RoomEvent(type, json)
 {
     if (callId().isEmpty())
diff --git a/lib/events/roomevent.h b/lib/events/roomevent.h
index 5670f55f..9461340b 100644
--- a/lib/events/roomevent.h
+++ b/lib/events/roomevent.h
@@ -96,8 +96,13 @@ public:
     ~CallEventBase() override = default;
     bool isCallEvent() const override { return true; }
 
-    QString callId() const { return contentPart<QString>("call_id"_ls); }
-    int version() const { return contentPart<int>("version"_ls); }
+    QUO_CONTENT_GETTER(QString, callId)
+    QUO_CONTENT_GETTER(int, version)
+
+protected:
+    static QJsonObject basicJson(const QString& matrixType,
+                                 const QString& callId, int version,
+                                 QJsonObject contentJson = {});
 };
 } // namespace Quotient
 Q_DECLARE_METATYPE(Quotient::RoomEvent*)
diff --git a/lib/events/roomkeyevent.h b/lib/events/roomkeyevent.h
index cb3fe7e7..9eb2854b 100644
--- a/lib/events/roomkeyevent.h
+++ b/lib/events/roomkeyevent.h
@@ -12,12 +12,17 @@ public:
     DEFINE_EVENT_TYPEID("m.room_key", RoomKeyEvent)
 
     explicit RoomKeyEvent(const QJsonObject& obj);
-    explicit RoomKeyEvent(const QString& algorithm, const QString& roomId, const QString &sessionId, const QString& sessionKey, const QString& senderId);
+    explicit RoomKeyEvent(const QString& algorithm, const QString& roomId,
+                          const QString& sessionId, const QString& sessionKey,
+                          const QString& senderId);
 
-    QString algorithm() const { return contentPart<QString>("algorithm"_ls); }
-    QString roomId() const { return contentPart<QString>(RoomIdKeyL); }
-    QString sessionId() const { return contentPart<QString>("session_id"_ls); }
-    QString sessionKey() const { return contentPart<QString>("session_key"_ls); }
+    QUO_CONTENT_GETTER(QString, algorithm)
+    QUO_CONTENT_GETTER(QString, roomId)
+    QUO_CONTENT_GETTER(QString, sessionId)
+    QByteArray sessionKey() const
+    {
+        return contentPart<QString>("session_key"_ls).toLatin1();
+    }
 };
 REGISTER_EVENT_TYPE(RoomKeyEvent)
 } // namespace Quotient
diff --git a/lib/events/roommemberevent.cpp b/lib/events/roommemberevent.cpp
index b4770224..953ff8ae 100644
--- a/lib/events/roommemberevent.cpp
+++ b/lib/events/roommemberevent.cpp
@@ -4,8 +4,6 @@
 
 #include "roommemberevent.h"
 
-#include "logging.h"
-
 #include <QtCore/QtAlgorithms>
 
 namespace Quotient {
@@ -13,18 +11,10 @@ template <>
 struct JsonConverter<Membership> {
     static Membership load(const QJsonValue& jv)
     {
-        const auto& ms = jv.toString();
-        if (ms.isEmpty())
-        {
-            qCWarning(EVENTS) << "Empty membership state";
-            return Membership::Invalid;
-        }
-        const auto it =
-            std::find(MembershipStrings.begin(), MembershipStrings.end(), ms);
-        if (it != MembershipStrings.end())
-            return Membership(1U << (it - MembershipStrings.begin()));
-
-        qCWarning(EVENTS) << "Unknown Membership value: " << ms;
+        if (const auto& ms = jv.toString(); !ms.isEmpty())
+            return flagFromJsonString<Membership>(ms, MembershipStrings);
+
+        qCWarning(EVENTS) << "Empty membership state";
         return Membership::Invalid;
     }
 };
@@ -43,19 +33,19 @@ MemberEventContent::MemberEventContent(const QJsonObject& json)
         displayName = sanitized(*displayName);
 }
 
-void MemberEventContent::fillJson(QJsonObject* o) const
+QJsonObject MemberEventContent::toJson() const
 {
-    Q_ASSERT(o);
+    QJsonObject o;
     if (membership != Membership::Invalid)
-        o->insert(QStringLiteral("membership"),
-                  MembershipStrings[qCountTrailingZeroBits(
-                      std::underlying_type_t<Membership>(membership))]);
+        o.insert(QStringLiteral("membership"),
+                 flagToJsonString(membership, MembershipStrings));
     if (displayName)
-        o->insert(QStringLiteral("displayname"), *displayName);
+        o.insert(QStringLiteral("displayname"), *displayName);
     if (avatarUrl && avatarUrl->isValid())
-        o->insert(QStringLiteral("avatar_url"), avatarUrl->toString());
+        o.insert(QStringLiteral("avatar_url"), avatarUrl->toString());
     if (!reason.isEmpty())
-        o->insert(QStringLiteral("reason"), reason);
+        o.insert(QStringLiteral("reason"), reason);
+    return o;
 }
 
 bool RoomMemberEvent::changesMembership() const
diff --git a/lib/events/roommemberevent.h b/lib/events/roommemberevent.h
index ceb7826b..dd33ea6b 100644
--- a/lib/events/roommemberevent.h
+++ b/lib/events/roommemberevent.h
@@ -5,18 +5,18 @@
 
 #pragma once
 
-#include "eventcontent.h"
 #include "stateevent.h"
 #include "quotient_common.h"
 
 namespace Quotient {
-class QUOTIENT_API MemberEventContent : public EventContent::Base {
+class QUOTIENT_API MemberEventContent {
 public:
     using MembershipType
         [[deprecated("Use Quotient::Membership instead")]] = Membership;
 
     QUO_IMPLICIT MemberEventContent(Membership ms) : membership(ms) {}
     explicit MemberEventContent(const QJsonObject& json);
+    QJsonObject toJson() const;
 
     Membership membership;
     /// (Only for invites) Whether the invite is to a direct chat
@@ -24,9 +24,6 @@ public:
     Omittable<QString> displayName;
     Omittable<QUrl> avatarUrl;
     QString reason;
-
-protected:
-    void fillJson(QJsonObject* o) const override;
 };
 
 using MembershipType [[deprecated("Use Membership instead")]] = Membership;
diff --git a/lib/events/roommessageevent.cpp b/lib/events/roommessageevent.cpp
index d63352cb..2a6ae93c 100644
--- a/lib/events/roommessageevent.cpp
+++ b/lib/events/roommessageevent.cpp
@@ -148,21 +148,21 @@ TypedBase* contentFromFile(const QFileInfo& file, bool asGenericFile)
         auto mimeTypeName = mimeType.name();
         if (mimeTypeName.startsWith("image/"))
             return new ImageContent(localUrl, file.size(), mimeType,
-                                    QImageReader(filePath).size(), none,
+                                    QImageReader(filePath).size(),
                                     file.fileName());
 
         // duration can only be obtained asynchronously and can only be reliably
         // done by starting to play the file. Left for a future implementation.
         if (mimeTypeName.startsWith("video/"))
             return new VideoContent(localUrl, file.size(), mimeType,
-                                    QMediaResource(localUrl).resolution(), none,
+                                    QMediaResource(localUrl).resolution(),
                                     file.fileName());
 
         if (mimeTypeName.startsWith("audio/"))
-            return new AudioContent(localUrl, file.size(), mimeType, none,
+            return new AudioContent(localUrl, file.size(), mimeType,
                                     file.fileName());
     }
-    return new FileContent(localUrl, file.size(), mimeType, none, file.fileName());
+    return new FileContent(localUrl, file.size(), mimeType, file.fileName());
 }
 
 RoomMessageEvent::RoomMessageEvent(const QString& plainBody,
@@ -302,17 +302,16 @@ TextContent::TextContent(const QJsonObject& json)
     }
 }
 
-void TextContent::fillJson(QJsonObject* json) const
+void TextContent::fillJson(QJsonObject &json) const
 {
     static const auto FormatKey = QStringLiteral("format");
 
-    Q_ASSERT(json);
     if (mimeType.inherits("text/html")) {
-        json->insert(FormatKey, HtmlContentTypeId);
-        json->insert(FormattedBodyKey, body);
+        json.insert(FormatKey, HtmlContentTypeId);
+        json.insert(FormattedBodyKey, body);
     }
     if (relatesTo) {
-        json->insert(
+        json.insert(
             QStringLiteral("m.relates_to"),
             relatesTo->type == EventRelation::ReplyType
                 ? QJsonObject { { relatesTo->type,
@@ -326,7 +325,7 @@ void TextContent::fillJson(QJsonObject* json) const
                 newContentJson.insert(FormatKey, HtmlContentTypeId);
                 newContentJson.insert(FormattedBodyKey, body);
             }
-            json->insert(QStringLiteral("m.new_content"), newContentJson);
+            json.insert(QStringLiteral("m.new_content"), newContentJson);
         }
     }
 }
@@ -347,9 +346,8 @@ QMimeType LocationContent::type() const
     return QMimeDatabase().mimeTypeForData(geoUri.toLatin1());
 }
 
-void LocationContent::fillJson(QJsonObject* o) const
+void LocationContent::fillJson(QJsonObject& o) const
 {
-    Q_ASSERT(o);
-    o->insert(QStringLiteral("geo_uri"), geoUri);
-    o->insert(QStringLiteral("info"), toInfoJson(thumbnail));
+    o.insert(QStringLiteral("geo_uri"), geoUri);
+    o.insert(QStringLiteral("info"), toInfoJson(thumbnail));
 }
diff --git a/lib/events/roommessageevent.h b/lib/events/roommessageevent.h
index 03a51328..6968ad70 100644
--- a/lib/events/roommessageevent.h
+++ b/lib/events/roommessageevent.h
@@ -136,7 +136,7 @@ namespace EventContent {
         Omittable<EventRelation> relatesTo;
 
     protected:
-        void fillJson(QJsonObject* json) const override;
+        void fillJson(QJsonObject& json) const override;
     };
 
     /**
@@ -164,28 +164,25 @@ namespace EventContent {
         Thumbnail thumbnail;
 
     protected:
-        void fillJson(QJsonObject* o) const override;
+        void fillJson(QJsonObject& o) const override;
     };
 
     /**
      * A base class for info types that include duration: audio and video
      */
-    template <typename ContentT>
-    class QUOTIENT_API PlayableContent : public ContentT {
+    template <typename InfoT>
+    class PlayableContent : public UrlBasedContent<InfoT> {
     public:
-        using ContentT::ContentT;
+        using UrlBasedContent<InfoT>::UrlBasedContent;
         PlayableContent(const QJsonObject& json)
-            : ContentT(json)
-            , duration(ContentT::originalInfoJson["duration"_ls].toInt())
+            : UrlBasedContent<InfoT>(json)
+            , duration(FileInfo::originalInfoJson["duration"_ls].toInt())
         {}
 
     protected:
-        void fillJson(QJsonObject* json) const override
+        void fillInfoJson(QJsonObject& infoJson) const override
         {
-            ContentT::fillJson(json);
-            auto infoJson = json->take("info"_ls).toObject();
             infoJson.insert(QStringLiteral("duration"), duration);
-            json->insert(QStringLiteral("info"), infoJson);
         }
 
     public:
@@ -211,7 +208,7 @@ namespace EventContent {
      *   - mimeType
      *   - imageSize
      */
-    using VideoContent = PlayableContent<UrlWithThumbnailContent<ImageInfo>>;
+    using VideoContent = PlayableContent<ImageInfo>;
 
     /**
      * Content class for m.audio
@@ -224,7 +221,13 @@ namespace EventContent {
      *   - payloadSize ("size" in JSON)
      *   - mimeType ("mimetype" in JSON)
      *   - duration
+     *   - thumbnail.url ("thumbnail_url" in JSON - extension to the spec)
+     * - corresponding to the "info/thumbnail_info" subobject: contents of
+     *   thumbnail field (extension to the spec):
+     *   - payloadSize
+     *   - mimeType
+     *   - imageSize
      */
-    using AudioContent = PlayableContent<UrlBasedContent<FileInfo>>;
+    using AudioContent = PlayableContent<FileInfo>;
 } // namespace EventContent
 } // namespace Quotient
diff --git a/lib/events/roompowerlevelsevent.cpp b/lib/events/roompowerlevelsevent.cpp
index 8d262ddf..d9bd010b 100644
--- a/lib/events/roompowerlevelsevent.cpp
+++ b/lib/events/roompowerlevelsevent.cpp
@@ -3,10 +3,10 @@
 
 #include "roompowerlevelsevent.h"
 
-#include <QJsonDocument>
-
 using namespace Quotient;
 
+// The default values used below are defined in
+// https://spec.matrix.org/v1.3/client-server-api/#mroompower_levels
 PowerLevelsEventContent::PowerLevelsEventContent(const QJsonObject& json) :
     invite(json["invite"_ls].toInt(50)),
     kick(json["kick"_ls].toInt(50)),
@@ -18,48 +18,36 @@ PowerLevelsEventContent::PowerLevelsEventContent(const QJsonObject& json) :
     users(fromJson<QHash<QString, int>>(json["users"_ls])),
     usersDefault(json["users_default"_ls].toInt(0)),
     notifications(Notifications{json["notifications"_ls].toObject()["room"_ls].toInt(50)})
-{
-}
+{}
 
-void PowerLevelsEventContent::fillJson(QJsonObject* o) const {
-    o->insert(QStringLiteral("invite"), invite);
-    o->insert(QStringLiteral("kick"), kick);
-    o->insert(QStringLiteral("ban"), ban);
-    o->insert(QStringLiteral("redact"), redact);
-    o->insert(QStringLiteral("events"), Quotient::toJson(events));
-    o->insert(QStringLiteral("events_default"), eventsDefault);
-    o->insert(QStringLiteral("state_default"), stateDefault);
-    o->insert(QStringLiteral("users"), Quotient::toJson(users));
-    o->insert(QStringLiteral("users_default"), usersDefault);
-    o->insert(QStringLiteral("notifications"), QJsonObject{{"room", notifications.room}});
+QJsonObject PowerLevelsEventContent::toJson() const
+{
+    QJsonObject o;
+    o.insert(QStringLiteral("invite"), invite);
+    o.insert(QStringLiteral("kick"), kick);
+    o.insert(QStringLiteral("ban"), ban);
+    o.insert(QStringLiteral("redact"), redact);
+    o.insert(QStringLiteral("events"), Quotient::toJson(events));
+    o.insert(QStringLiteral("events_default"), eventsDefault);
+    o.insert(QStringLiteral("state_default"), stateDefault);
+    o.insert(QStringLiteral("users"), Quotient::toJson(users));
+    o.insert(QStringLiteral("users_default"), usersDefault);
+    o.insert(QStringLiteral("notifications"),
+             QJsonObject { { "room", notifications.room } });
+    return o;
 }
 
-int RoomPowerLevelsEvent::powerLevelForEvent(const QString &eventId) const {
-    auto e = events();
-
-    if (e.contains(eventId)) {
-        return e[eventId];
-    }
-
-    return eventsDefault();
+int RoomPowerLevelsEvent::powerLevelForEvent(const QString& eventId) const
+{
+    return events().value(eventId, eventsDefault());
 }
 
-int RoomPowerLevelsEvent::powerLevelForState(const QString &eventId) const {
-    auto e = events();
-
-    if (e.contains(eventId)) {
-        return e[eventId];
-    }
-
-    return stateDefault();
+int RoomPowerLevelsEvent::powerLevelForState(const QString& eventId) const
+{
+    return events().value(eventId, stateDefault());
 }
 
-int RoomPowerLevelsEvent::powerLevelForUser(const QString &userId) const {
-    auto u = users();
-
-    if (u.contains(userId)) {
-        return u[userId];
-    }
-
-    return usersDefault();
+int RoomPowerLevelsEvent::powerLevelForUser(const QString& userId) const
+{
+    return users().value(userId, usersDefault());
 }
diff --git a/lib/events/roompowerlevelsevent.h b/lib/events/roompowerlevelsevent.h
index 415cc814..a1638a27 100644
--- a/lib/events/roompowerlevelsevent.h
+++ b/lib/events/roompowerlevelsevent.h
@@ -3,17 +3,16 @@
 
 #pragma once
 
-#include "eventcontent.h"
 #include "stateevent.h"
 
 namespace Quotient {
-class QUOTIENT_API PowerLevelsEventContent : public EventContent::Base {
-public:
+struct QUOTIENT_API PowerLevelsEventContent {
     struct Notifications {
         int room;
     };
 
     explicit PowerLevelsEventContent(const QJsonObject& json);
+    QJsonObject toJson() const;
 
     int invite;
     int kick;
@@ -29,9 +28,6 @@ public:
     int usersDefault;
 
     Notifications notifications;
-
-protected:
-    void fillJson(QJsonObject* o) const override;
 };
 
 class QUOTIENT_API RoomPowerLevelsEvent
diff --git a/lib/events/simplestateevents.h b/lib/events/simplestateevents.h
index 9610574b..a8eaab56 100644
--- a/lib/events/simplestateevents.h
+++ b/lib/events/simplestateevents.h
@@ -4,65 +4,51 @@
 #pragma once
 
 #include "stateevent.h"
+#include "single_key_value.h"
 
 namespace Quotient {
-namespace EventContent {
-    template <typename T>
-    struct SimpleContent {
-        using value_type = T;
-
-        // The constructor is templated to enable perfect forwarding
-        template <typename TT>
-        SimpleContent(QString keyName, TT&& value)
-            : value(std::forward<TT>(value)), key(std::move(keyName))
-        {}
-        SimpleContent(const QJsonObject& json, QString keyName)
-            : value(fromJson<T>(json[keyName])), key(std::move(keyName))
-        {}
-        QJsonObject toJson() const
-        {
-            return { { key, Quotient::toJson(value) } };
-        }
-
-        T value;
-        const QString key;
-    };
-} // namespace EventContent
-
-#define DEFINE_SIMPLE_STATE_EVENT(_Name, _TypeId, _ValueType, _ContentKey)     \
-    class QUOTIENT_API _Name                                                \
-        : public StateEvent<EventContent::SimpleContent<_ValueType>> {         \
-    public:                                                                    \
-        using value_type = content_type::value_type;                           \
-        DEFINE_EVENT_TYPEID(_TypeId, _Name)                                    \
-        template <typename T>                                                  \
-        explicit _Name(T&& value)                                              \
-            : StateEvent(typeId(), matrixTypeId(), QString(),                  \
-                         QStringLiteral(#_ContentKey), std::forward<T>(value)) \
-        {}                                                                     \
-        explicit _Name(QJsonObject obj)                                        \
-            : StateEvent(typeId(), std::move(obj),                             \
-                         QStringLiteral(#_ContentKey))                         \
-        {}                                                                     \
-        auto _ContentKey() const { return content().value; }                   \
-    };                                                                         \
-    REGISTER_EVENT_TYPE(_Name)                                                 \
+#define DEFINE_SIMPLE_STATE_EVENT(_Name, _TypeId, _ValueType, _ContentKey) \
+    constexpr auto _Name##Key = #_ContentKey##_ls;                         \
+    class QUOTIENT_API _Name                                               \
+        : public StateEvent<                                               \
+              EventContent::SingleKeyValue<_ValueType, &_Name##Key>> {     \
+    public:                                                                \
+        using value_type = _ValueType;                                     \
+        DEFINE_EVENT_TYPEID(_TypeId, _Name)                                \
+        template <typename T>                                              \
+        explicit _Name(T&& value)                                          \
+            : StateEvent(TypeId, matrixTypeId(), QString(),                \
+                         std::forward<T>(value))                           \
+        {}                                                                 \
+        explicit _Name(QJsonObject obj)                                    \
+            : StateEvent(TypeId, std::move(obj))                           \
+        {}                                                                 \
+        auto _ContentKey() const { return content().value; }               \
+    };                                                                     \
+    REGISTER_EVENT_TYPE(_Name)                                             \
     // End of macro
 
 DEFINE_SIMPLE_STATE_EVENT(RoomNameEvent, "m.room.name", QString, name)
 DEFINE_SIMPLE_STATE_EVENT(RoomTopicEvent, "m.room.topic", QString, topic)
-DEFINE_SIMPLE_STATE_EVENT(RoomPinnedEvent, "m.room.pinned_messages", QStringList, pinnedEvents)
+DEFINE_SIMPLE_STATE_EVENT(RoomPinnedEvent, "m.room.pinned_messages",
+                          QStringList, pinnedEvents)
 
-class [[deprecated(
-    "m.room.aliases events are deprecated by the Matrix spec; use"
-    " RoomCanonicalAliasEvent::altAliases() to get non-authoritative aliases")]] //
-RoomAliasesEvent : public StateEvent<EventContent::SimpleContent<QStringList>> {
+constexpr auto RoomAliasesEventKey = "aliases"_ls;
+class QUOTIENT_API RoomAliasesEvent
+    : public StateEvent<
+          EventContent::SingleKeyValue<QStringList, &RoomAliasesEventKey>> {
 public:
     DEFINE_EVENT_TYPEID("m.room.aliases", RoomAliasesEvent)
     explicit RoomAliasesEvent(const QJsonObject& obj)
-        : StateEvent(typeId(), obj, QStringLiteral("aliases"))
+        : StateEvent(typeId(), obj)
     {}
+    Q_DECL_DEPRECATED_X(
+        "m.room.aliases events are deprecated by the Matrix spec; use"
+        " RoomCanonicalAliasEvent::altAliases() to get non-authoritative aliases")
     QString server() const { return stateKey(); }
+    Q_DECL_DEPRECATED_X(
+        "m.room.aliases events are deprecated by the Matrix spec; use"
+        " RoomCanonicalAliasEvent::altAliases() to get non-authoritative aliases")
     QStringList aliases() const { return content().value; }
 };
 } // namespace Quotient
diff --git a/lib/events/single_key_value.h b/lib/events/single_key_value.h
new file mode 100644
index 00000000..75ca8cd2
--- /dev/null
+++ b/lib/events/single_key_value.h
@@ -0,0 +1,27 @@
+#pragma once
+
+#include "converters.h"
+
+namespace Quotient {
+
+namespace EventContent {
+    template <typename T, const QLatin1String* KeyStr>
+    struct SingleKeyValue {
+        T value;
+    };
+} // namespace EventContent
+
+template <typename ValueT, const QLatin1String* KeyStr>
+struct JsonConverter<EventContent::SingleKeyValue<ValueT, KeyStr>> {
+    using content_type = EventContent::SingleKeyValue<ValueT, KeyStr>;
+    static content_type load(const QJsonValue& jv)
+    {
+        return { fromJson<ValueT>(jv.toObject().value(JsonKey)) };
+    }
+    static QJsonObject dump(const content_type& c)
+    {
+        return { { JsonKey, toJson(c.value) } };
+    }
+    static inline const auto JsonKey = toSnakeCase(*KeyStr);
+};
+} // namespace Quotient
diff --git a/lib/events/stateevent.cpp b/lib/events/stateevent.cpp
index e53d47d4..1df24df0 100644
--- a/lib/events/stateevent.cpp
+++ b/lib/events/stateevent.cpp
@@ -6,9 +6,9 @@
 using namespace Quotient;
 
 StateEventBase::StateEventBase(Type type, const QJsonObject& json)
-    : RoomEvent(json.contains(StateKeyKeyL) ? type : unknownEventTypeId(), json)
+    : RoomEvent(json.contains(StateKeyKeyL) ? type : UnknownEventTypeId, json)
 {
-    if (Event::type() == unknownEventTypeId() && !json.contains(StateKeyKeyL))
+    if (Event::type() == UnknownEventTypeId && !json.contains(StateKeyKeyL))
         qWarning(EVENTS) << "Attempt to create a state event with no stateKey -"
                             "forcing the event type to unknown to avoid damage";
 }
@@ -16,12 +16,12 @@ StateEventBase::StateEventBase(Type type, const QJsonObject& json)
 StateEventBase::StateEventBase(Event::Type type, event_mtype_t matrixType,
                                const QString& stateKey,
                                const QJsonObject& contentJson)
-    : RoomEvent(type, basicStateEventJson(matrixType, contentJson, stateKey))
+    : RoomEvent(type, basicJson(type, stateKey, contentJson))
 {}
 
 bool StateEventBase::repeatsState() const
 {
-    const auto prevContentJson = unsignedPart(PrevContentKeyL);
+    const auto prevContentJson = unsignedPart<QJsonObject>(PrevContentKeyL);
     return fullJson().value(ContentKeyL) == prevContentJson;
 }
 
diff --git a/lib/events/stateevent.h b/lib/events/stateevent.h
index 88da68f8..9f1d7118 100644
--- a/lib/events/stateevent.h
+++ b/lib/events/stateevent.h
@@ -7,16 +7,6 @@
 
 namespace Quotient {
 
-/// Make a minimal correct Matrix state event JSON
-inline QJsonObject basicStateEventJson(const QString& matrixTypeId,
-                                       const QJsonObject& content,
-                                       const QString& stateKey = {})
-{
-    return { { TypeKey, matrixTypeId },
-             { StateKeyKey, stateKey },
-             { ContentKey, content } };
-}
-
 class QUOTIENT_API StateEventBase : public RoomEvent {
 public:
     static inline EventFactory<StateEventBase> factory { "StateEvent" };
@@ -27,6 +17,16 @@ public:
                    const QJsonObject& contentJson = {});
     ~StateEventBase() override = default;
 
+    //! Make a minimal correct Matrix state event JSON
+    static QJsonObject basicJson(const QString& matrixTypeId,
+                                 const QString& stateKey = {},
+                                 const QJsonObject& contentJson = {})
+    {
+        return { { TypeKey, matrixTypeId },
+                 { StateKeyKey, stateKey },
+                 { ContentKey, contentJson } };
+    }
+
     bool isStateEvent() const override { return true; }
     QString replacedState() const;
     void dumpTo(QDebug dbg) const override;
@@ -36,6 +36,14 @@ public:
 using StateEventPtr = event_ptr_tt<StateEventBase>;
 using StateEvents = EventsArray<StateEventBase>;
 
+[[deprecated("Use StateEventBase::basicJson() instead")]]
+inline QJsonObject basicStateEventJson(const QString& matrixTypeId,
+                                       const QJsonObject& content,
+                                       const QString& stateKey = {})
+{
+    return StateEventBase::basicJson(matrixTypeId, stateKey, content);
+}
+
 //! \brief Override RoomEvent factory with that from StateEventBase if JSON has
 //! stateKey
 //!
@@ -64,7 +72,7 @@ inline bool is<StateEventBase>(const Event& e)
  * \sa
  * https://matrix.org/docs/spec/client_server/unstable.html#types-of-room-events
  */
-using StateEventKey = QPair<QString, QString>;
+using StateEventKey = std::pair<QString, QString>;
 
 template <typename ContentT>
 struct Prev {
@@ -72,7 +80,7 @@ struct Prev {
     explicit Prev(const QJsonObject& unsignedJson,
                   ContentParamTs&&... contentParams)
         : senderId(unsignedJson.value("prev_sender"_ls).toString())
-        , content(unsignedJson.value(PrevContentKeyL).toObject(),
+        , content(fromJson<ContentT>(unsignedJson.value(PrevContentKeyL)),
                   std::forward<ContentParamTs>(contentParams)...)
     {}
 
@@ -89,7 +97,8 @@ public:
     explicit StateEvent(Type type, const QJsonObject& fullJson,
                         ContentParamTs&&... contentParams)
         : StateEventBase(type, fullJson)
-        , _content(contentJson(), std::forward<ContentParamTs>(contentParams)...)
+        , _content(fromJson<ContentT>(contentJson()),
+                   std::forward<ContentParamTs>(contentParams)...)
     {
         const auto& unsignedData = unsignedJson();
         if (unsignedData.contains(PrevContentKeyL))
@@ -101,9 +110,9 @@ public:
                         const QString& stateKey,
                         ContentParamTs&&... contentParams)
         : StateEventBase(type, matrixType, stateKey)
-        , _content(std::forward<ContentParamTs>(contentParams)...)
+        , _content{std::forward<ContentParamTs>(contentParams)...}
     {
-        editJson().insert(ContentKey, _content.toJson());
+        editJson().insert(ContentKey, toJson(_content));
     }
 
     const ContentT& content() const { return _content; }
@@ -111,7 +120,7 @@ public:
     void editContent(VisitorT&& visitor)
     {
         visitor(_content);
-        editJson()[ContentKeyL] = _content.toJson();
+        editJson()[ContentKeyL] = toJson(_content);
     }
     const ContentT* prevContent() const
     {
diff --git a/lib/events/stickerevent.cpp b/lib/events/stickerevent.cpp
deleted file mode 100644
index 628fd154..00000000
--- a/lib/events/stickerevent.cpp
+++ /dev/null
@@ -1,26 +0,0 @@
-// SDPX-FileCopyrightText: 2020 Carl Schwan <carlschwan@kde.org>
-// SPDX-License-Identifier: LGPL-2.1-or-later
-
-#include "stickerevent.h"
-
-using namespace Quotient;
-
-StickerEvent::StickerEvent(const QJsonObject &obj)
-    : RoomEvent(typeId(), obj)
-    , m_imageContent(EventContent::ImageContent(obj["content"_ls].toObject()))
-{}
-
-QString StickerEvent::body() const
-{
-    return contentPart<QString>("body"_ls);
-}
-
-const EventContent::ImageContent &StickerEvent::image() const
-{
-    return m_imageContent;
-}
-
-QUrl StickerEvent::url() const
-{
-    return m_imageContent.url;
-}
diff --git a/lib/events/stickerevent.h b/lib/events/stickerevent.h
index 0957dca3..e378422d 100644
--- a/lib/events/stickerevent.h
+++ b/lib/events/stickerevent.h
@@ -16,21 +16,32 @@ class QUOTIENT_API StickerEvent : public RoomEvent
 public:
     DEFINE_EVENT_TYPEID("m.sticker", StickerEvent)
 
-    explicit StickerEvent(const QJsonObject &obj);
+    explicit StickerEvent(const QJsonObject& obj)
+        : RoomEvent(TypeId, obj)
+        , m_imageContent(
+              EventContent::ImageContent(obj["content"_ls].toObject()))
+    {}
 
     /// \brief A textual representation or associated description of the
     /// sticker image.
     ///
     /// This could be the alt text of the original image, or a message to
     /// accompany and further describe the sticker.
-    QString body() const;
+    QUO_CONTENT_GETTER(QString, body)
 
     /// \brief Metadata about the image referred to in url including a
     /// thumbnail representation.
-    const EventContent::ImageContent &image() const;
+    const EventContent::ImageContent& image() const
+    {
+        return m_imageContent;
+    }
 
     /// \brief The URL to the sticker image. This must be a valid mxc:// URI.
-    QUrl url() const;
+    QUrl url() const
+    {
+        return m_imageContent.url();
+    }
+
 private:
     EventContent::ImageContent m_imageContent;
 };
diff --git a/lib/expected.h b/lib/expected.h
new file mode 100644
index 00000000..7b9e7f1d
--- /dev/null
+++ b/lib/expected.h
@@ -0,0 +1,77 @@
+// SPDX-FileCopyrightText: 2022 Kitsune Ral <Kitsune-Ral@users.sf.net>
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+#include <variant>
+
+namespace Quotient {
+
+//! \brief A minimal subset of std::expected from C++23
+template <typename T, typename E,
+          std::enable_if_t<!std::is_same_v<T, E>, bool> = true>
+class Expected {
+private:
+    template <typename X>
+    using enable_if_constructible_t = std::enable_if_t<
+        std::is_constructible_v<T, X> || std::is_constructible_v<E, X>>;
+
+public:
+    using value_type = T;
+    using error_type = E;
+
+    Expected() = default;
+    explicit Expected(const Expected&) = default;
+    explicit Expected(Expected&&) noexcept = default;
+
+    template <typename X, typename = enable_if_constructible_t<X>>
+    Expected(X&& x)
+        : data(std::forward<X>(x))
+    {}
+
+    Expected& operator=(const Expected&) = default;
+    Expected& operator=(Expected&&) noexcept = default;
+
+    template <typename X, typename = enable_if_constructible_t<X>>
+    Expected& operator=(X&& x)
+    {
+        data = std::forward<X>(x);
+        return *this;
+    }
+
+    bool has_value() const { return std::holds_alternative<T>(data); }
+    explicit operator bool() const { return has_value(); }
+
+    const value_type& value() const& { return std::get<T>(data); }
+    value_type& value() & { return std::get<T>(data); }
+    value_type value() && { return std::get<T>(std::move(data)); }
+
+    const value_type& operator*() const& { return value(); }
+    value_type& operator*() & { return value(); }
+
+    const value_type* operator->() const& { return std::get_if<T>(&data); }
+    value_type* operator->() & { return std::get_if<T>(&data); }
+
+    template <class U>
+    T value_or(U&& fallback) const&
+    {
+        if (has_value())
+            return value();
+        return std::forward<U>(fallback);
+    }
+    template <class U>
+    T value_or(U&& fallback) &&
+    {
+        if (has_value())
+            return value();
+        return std::forward<U>(fallback);
+    }
+
+    const E& error() const& { return std::get<E>(data); }
+    E& error() & { return std::get<E>(data); }
+
+private:
+    std::variant<T, E> data;
+};
+
+} // namespace Quotient
diff --git a/lib/function_traits.cpp b/lib/function_traits.cpp
index 6542101a..e3d27122 100644
--- a/lib/function_traits.cpp
+++ b/lib/function_traits.cpp
@@ -7,6 +7,9 @@
 
 using namespace Quotient;
 
+template <typename FnT>
+using fn_return_t = typename function_traits<FnT>::return_type;
+
 int f_();
 static_assert(std::is_same_v<fn_return_t<decltype(f_)>, int>,
               "Test fn_return_t<>");
diff --git a/lib/function_traits.h b/lib/function_traits.h
index 83b8e425..143ed162 100644
--- a/lib/function_traits.h
+++ b/lib/function_traits.h
@@ -8,7 +8,7 @@
 namespace Quotient {
 
 namespace _impl {
-    template <typename AlwaysVoid, typename>
+    template <typename>
     struct fn_traits {};
 }
 
@@ -21,73 +21,73 @@ namespace _impl {
  */
 template <typename T>
 struct function_traits
-    : public _impl::fn_traits<void, std::remove_reference_t<T>> {};
+    : public _impl::fn_traits<std::remove_reference_t<T>> {};
 
 // Specialisation for a function
 template <typename ReturnT, typename... ArgTs>
 struct function_traits<ReturnT(ArgTs...)> {
     using return_type = ReturnT;
     using arg_types = std::tuple<ArgTs...>;
-    // See also the comment for wrap_in_function() in qt_connection_util.h
-    using function_type = std::function<ReturnT(ArgTs...)>;
 };
 
 namespace _impl {
-    template <typename AlwaysVoid, typename>
+    template <typename>
     struct fn_object_traits;
 
     // Specialisation for a lambda function
     template <typename ReturnT, typename ClassT, typename... ArgTs>
-    struct fn_object_traits<void, ReturnT (ClassT::*)(ArgTs...)>
+    struct fn_object_traits<ReturnT (ClassT::*)(ArgTs...)>
         : function_traits<ReturnT(ArgTs...)> {};
 
     // Specialisation for a const lambda function
     template <typename ReturnT, typename ClassT, typename... ArgTs>
-    struct fn_object_traits<void, ReturnT (ClassT::*)(ArgTs...) const>
+    struct fn_object_traits<ReturnT (ClassT::*)(ArgTs...) const>
         : function_traits<ReturnT(ArgTs...)> {};
 
     // Specialisation for function objects with (non-overloaded) operator()
     // (this includes non-generic lambdas)
     template <typename T>
-    struct fn_traits<decltype(void(&T::operator())), T>
-        : public fn_object_traits<void, decltype(&T::operator())> {};
+    requires requires { &T::operator(); }
+    struct fn_traits<T>
+        : public fn_object_traits<decltype(&T::operator())> {};
 
     // Specialisation for a member function in a non-functor class
     template <typename ReturnT, typename ClassT, typename... ArgTs>
-    struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...)>
+    struct fn_traits<ReturnT (ClassT::*)(ArgTs...)>
         : function_traits<ReturnT(ClassT, ArgTs...)> {};
 
     // Specialisation for a const member function
     template <typename ReturnT, typename ClassT, typename... ArgTs>
-    struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...) const>
+    struct fn_traits<ReturnT (ClassT::*)(ArgTs...) const>
         : function_traits<ReturnT(const ClassT&, ArgTs...)> {};
 
     // Specialisation for a constref member function
     template <typename ReturnT, typename ClassT, typename... ArgTs>
-    struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...) const&>
+    struct fn_traits<ReturnT (ClassT::*)(ArgTs...) const&>
         : function_traits<ReturnT(const ClassT&, ArgTs...)> {};
 
     // Specialisation for a prvalue member function
     template <typename ReturnT, typename ClassT, typename... ArgTs>
-    struct fn_traits<void, ReturnT (ClassT::*)(ArgTs...) &&>
+    struct fn_traits<ReturnT (ClassT::*)(ArgTs...) &&>
         : function_traits<ReturnT(ClassT&&, ArgTs...)> {};
 
     // Specialisation for a pointer-to-member
     template <typename ReturnT, typename ClassT>
-    struct fn_traits<void, ReturnT ClassT::*>
+    struct fn_traits<ReturnT ClassT::*>
         : function_traits<ReturnT&(ClassT)> {};
 
     // Specialisation for a const pointer-to-member
     template <typename ReturnT, typename ClassT>
-    struct fn_traits<void, const ReturnT ClassT::*>
+    struct fn_traits<const ReturnT ClassT::*>
         : function_traits<const ReturnT&(ClassT)> {};
 } // namespace _impl
 
-template <typename FnT>
-using fn_return_t = typename function_traits<FnT>::return_type;
-
 template <typename FnT, int ArgN = 0>
 using fn_arg_t =
     std::tuple_element_t<ArgN, typename function_traits<FnT>::arg_types>;
 
+template <typename FnT>
+constexpr auto fn_arg_count_v =
+    std::tuple_size_v<typename function_traits<FnT>::arg_types>;
+
 } // namespace Quotient
diff --git a/lib/jobs/basejob.cpp b/lib/jobs/basejob.cpp
index b6858b5a..da645a2d 100644
--- a/lib/jobs/basejob.cpp
+++ b/lib/jobs/basejob.cpp
@@ -138,9 +138,8 @@ public:
     QTimer timer;
     QTimer retryTimer;
 
-    static constexpr std::array<const JobTimeoutConfig, 3> errorStrategy {
-        { { 90s, 5s }, { 90s, 10s }, { 120s, 30s } }
-    };
+    static constexpr auto errorStrategy = std::to_array<const JobTimeoutConfig>(
+        { { 90s, 5s }, { 90s, 10s }, { 120s, 30s } });
     int maxRetries = int(errorStrategy.size());
     int retriesTaken = 0;
 
@@ -152,10 +151,8 @@ public:
 
     [[nodiscard]] QString dumpRequest() const
     {
-        // FIXME: use std::array {} when Apple stdlib gets deduction guides for it
-        static const auto verbs =
-            make_array(QStringLiteral("GET"), QStringLiteral("PUT"),
-                       QStringLiteral("POST"), QStringLiteral("DELETE"));
+        static const std::array verbs { "GET"_ls, "PUT"_ls, "POST"_ls,
+                                        "DELETE"_ls };
         const auto verbWord = verbs.at(size_t(verb));
         return verbWord % ' '
                % (reply ? reply->url().toString(QUrl::RemoveQuery)
@@ -301,16 +298,10 @@ void BaseJob::Private::sendRequest()
                      QNetworkRequest::NoLessSafeRedirectPolicy);
     req.setMaximumRedirectsAllowed(10);
     req.setAttribute(QNetworkRequest::HttpPipeliningAllowedAttribute, true);
-    req.setAttribute(
-#if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
-        QNetworkRequest::Http2AllowedAttribute
-#else
-        QNetworkRequest::HTTP2AllowedAttribute
-#endif
     // Qt doesn't combine HTTP2 with SSL quite right, occasionally crashing at
     // what seems like an attempt to write to a closed channel. If/when that
     // changes, false should be turned to true below.
-        , false);
+    req.setAttribute(QNetworkRequest::Http2AllowedAttribute, false);
     Q_ASSERT(req.url().isValid());
     for (auto it = requestHeaders.cbegin(); it != requestHeaders.cend(); ++it)
         req.setRawHeader(it.key(), it.value());
@@ -754,11 +745,14 @@ QString BaseJob::statusCaption() const
     }
 }
 
-int BaseJob::error() const { return d->status.code; }
+int BaseJob::error() const {
+        return d->status.code; }
 
-QString BaseJob::errorString() const { return d->status.message; }
+QString BaseJob::errorString() const {
+        return d->status.message; }
 
-QUrl BaseJob::errorUrl() const { return d->errorUrl; }
+QUrl BaseJob::errorUrl() const {
+        return d->errorUrl; }
 
 void BaseJob::setStatus(Status s)
 {
diff --git a/lib/jobs/downloadfilejob.cpp b/lib/jobs/downloadfilejob.cpp
index d00fc5f4..759d52c9 100644
--- a/lib/jobs/downloadfilejob.cpp
+++ b/lib/jobs/downloadfilejob.cpp
@@ -8,8 +8,9 @@
 #include <QtNetwork/QNetworkReply>
 
 #ifdef Quotient_E2EE_ENABLED
-#   include <QtCore/QCryptographicHash>
-#   include "events/encryptedfile.h"
+#    include "events/filesourceinfo.h"
+
+#    include <QtCore/QCryptographicHash>
 #endif
 
 using namespace Quotient;
@@ -26,7 +27,7 @@ public:
     QScopedPointer<QFile> tempFile;
 
 #ifdef Quotient_E2EE_ENABLED
-    Omittable<EncryptedFile> encryptedFile;
+    Omittable<EncryptedFileMetadata> encryptedFileMetadata;
 #endif
 };
 
@@ -49,14 +50,14 @@ DownloadFileJob::DownloadFileJob(const QString& serverName,
 #ifdef Quotient_E2EE_ENABLED
 DownloadFileJob::DownloadFileJob(const QString& serverName,
                                  const QString& mediaId,
-                                 const EncryptedFile& file,
+                                 const EncryptedFileMetadata& file,
                                  const QString& localFilename)
     : GetContentJob(serverName, mediaId)
     , d(localFilename.isEmpty() ? makeImpl<Private>()
                                 : makeImpl<Private>(localFilename))
 {
     setObjectName(QStringLiteral("DownloadFileJob"));
-    d->encryptedFile = file;
+    d->encryptedFileMetadata = file;
 }
 #endif
 QString DownloadFileJob::targetFileName() const
@@ -118,27 +119,31 @@ void DownloadFileJob::beforeAbandon()
     d->tempFile->remove();
 }
 
+void decryptFile(QFile& sourceFile, const EncryptedFileMetadata& metadata,
+                 QFile& targetFile)
+{
+    sourceFile.seek(0);
+    const auto encrypted = sourceFile.readAll(); // TODO: stream decryption
+    const auto decrypted = decryptFile(encrypted, metadata);
+    targetFile.write(decrypted);
+}
+
 BaseJob::Status DownloadFileJob::prepareResult()
 {
     if (d->targetFile) {
 #ifdef Quotient_E2EE_ENABLED
-        if (d->encryptedFile.has_value()) {
-            d->tempFile->seek(0);
-            QByteArray encrypted = d->tempFile->readAll();
-
-            EncryptedFile file = *d->encryptedFile;
-            const auto decrypted = file.decryptFile(encrypted);
-            d->targetFile->write(decrypted);
+        if (d->encryptedFileMetadata.has_value()) {
+            decryptFile(*d->tempFile, *d->encryptedFileMetadata, *d->targetFile);
             d->tempFile->remove();
         } else {
 #endif
             d->targetFile->close();
             if (!d->targetFile->remove()) {
-                qCWarning(JOBS) << "Failed to remove the target file placeholder";
+                qWarning(JOBS) << "Failed to remove the target file placeholder";
                 return { FileError, "Couldn't finalise the download" };
             }
             if (!d->tempFile->rename(d->targetFile->fileName())) {
-                qCWarning(JOBS) << "Failed to rename" << d->tempFile->fileName()
+                qWarning(JOBS) << "Failed to rename" << d->tempFile->fileName()
                                 << "to" << d->targetFile->fileName();
                 return { FileError, "Couldn't finalise the download" };
             }
@@ -147,13 +152,20 @@ BaseJob::Status DownloadFileJob::prepareResult()
 #endif
     } else {
 #ifdef Quotient_E2EE_ENABLED
-        if (d->encryptedFile.has_value()) {
-            d->tempFile->seek(0);
-            const auto encrypted = d->tempFile->readAll();
-
-            EncryptedFile file = *d->encryptedFile;
-            const auto decrypted = file.decryptFile(encrypted);
-            d->tempFile->write(decrypted);
+        if (d->encryptedFileMetadata.has_value()) {
+            QTemporaryFile tempTempFile; // Assuming it to be next to tempFile
+            decryptFile(*d->tempFile, *d->encryptedFileMetadata, tempTempFile);
+            d->tempFile->close();
+            if (!d->tempFile->remove()) {
+                qWarning(JOBS)
+                    << "Failed to remove the decrypted file placeholder";
+                return { FileError, "Couldn't finalise the download" };
+            }
+            if (!tempTempFile.rename(d->tempFile->fileName())) {
+                qWarning(JOBS) << "Failed to rename" << tempTempFile.fileName()
+                                << "to" << d->tempFile->fileName();
+                return { FileError, "Couldn't finalise the download" };
+            }
         } else {
 #endif
             d->tempFile->close();
@@ -161,6 +173,6 @@ BaseJob::Status DownloadFileJob::prepareResult()
         }
 #endif
     }
-    qCDebug(JOBS) << "Saved a file as" << targetFileName();
+    qDebug(JOBS) << "Saved a file as" << targetFileName();
     return Success;
 }
diff --git a/lib/jobs/downloadfilejob.h b/lib/jobs/downloadfilejob.h
index ffa3d055..cbbfd244 100644
--- a/lib/jobs/downloadfilejob.h
+++ b/lib/jobs/downloadfilejob.h
@@ -4,7 +4,8 @@
 #pragma once
 
 #include "csapi/content-repo.h"
-#include "events/encryptedfile.h"
+
+#include "events/filesourceinfo.h"
 
 namespace Quotient {
 class QUOTIENT_API DownloadFileJob : public GetContentJob {
@@ -16,7 +17,7 @@ public:
                     const QString& localFilename = {});
 
 #ifdef Quotient_E2EE_ENABLED
-    DownloadFileJob(const QString& serverName, const QString& mediaId, const EncryptedFile& file, const QString& localFilename = {});
+    DownloadFileJob(const QString& serverName, const QString& mediaId, const EncryptedFileMetadata& file, const QString& localFilename = {});
 #endif
     QString targetFileName() const;
 
diff --git a/lib/jobs/requestdata.cpp b/lib/jobs/requestdata.cpp
index 2c001ccc..ab249f6d 100644
--- a/lib/jobs/requestdata.cpp
+++ b/lib/jobs/requestdata.cpp
@@ -14,7 +14,7 @@ using namespace Quotient;
 
 auto fromData(const QByteArray& data)
 {
-    auto source = std::make_unique<QBuffer>();
+    auto source = makeImpl<QBuffer, QIODevice>();
     source->setData(data);
     source->open(QIODevice::ReadOnly);
     return source;
@@ -33,7 +33,5 @@ RequestData::RequestData(const QJsonObject& jo) : _source(fromJson(jo)) {}
 RequestData::RequestData(const QJsonArray& ja) : _source(fromJson(ja)) {}
 
 RequestData::RequestData(QIODevice* source)
-    : _source(std::unique_ptr<QIODevice>(source))
+    : _source(acquireImpl(source))
 {}
-
-RequestData::~RequestData() = default;
diff --git a/lib/jobs/requestdata.h b/lib/jobs/requestdata.h
index 41ad833a..accc8f71 100644
--- a/lib/jobs/requestdata.h
+++ b/lib/jobs/requestdata.h
@@ -3,11 +3,7 @@
 
 #pragma once
 
-#include "quotient_export.h"
-
-#include <QtCore/QByteArray>
-
-#include <memory>
+#include "util.h"
 
 class QJsonObject;
 class QJsonArray;
@@ -23,17 +19,17 @@ namespace Quotient {
  */
 class QUOTIENT_API RequestData {
 public:
-    RequestData(const QByteArray& a = {});
-    RequestData(const QJsonObject& jo);
-    RequestData(const QJsonArray& ja);
-    RequestData(QIODevice* source);
-    RequestData(RequestData&&) = default;
-    RequestData& operator=(RequestData&&) = default;
-    ~RequestData();
+    // NOLINTBEGIN(google-explicit-constructor): that check should learn about
+    //                                           explicit(false)
+    QUO_IMPLICIT RequestData(const QByteArray& a = {});
+    QUO_IMPLICIT RequestData(const QJsonObject& jo);
+    QUO_IMPLICIT RequestData(const QJsonArray& ja);
+    QUO_IMPLICIT RequestData(QIODevice* source);
+    // NOLINTEND(google-explicit-constructor)
 
     QIODevice* source() const { return _source.get(); }
 
 private:
-    std::unique_ptr<QIODevice> _source;
+    ImplPtr<QIODevice> _source;
 };
 } // namespace Quotient
diff --git a/lib/jobs/syncjob.h b/lib/jobs/syncjob.h
index 830a7c71..b7bfbbb3 100644
--- a/lib/jobs/syncjob.h
+++ b/lib/jobs/syncjob.h
@@ -15,7 +15,7 @@ public:
     explicit SyncJob(const QString& since, const Filter& filter,
                      int timeout = -1, const QString& presence = {});
 
-    SyncData&& takeData() { return std::move(d); }
+    SyncData takeData() { return std::move(d); }
 
 protected:
     Status prepareResult() override;
diff --git a/lib/keyverificationsession.cpp b/lib/keyverificationsession.cpp
index 3b3b7627..d889b465 100644
--- a/lib/keyverificationsession.cpp
+++ b/lib/keyverificationsession.cpp
@@ -23,8 +23,10 @@ KeyVerificationSession::KeyVerificationSession(const QString& remoteUserId, cons
     , m_encrypted(encrypted)
     , m_remoteSupportedMethods(event.methods())
 {
-    auto timeoutTime = std::min<long int>(event.timestamp() + 600000, QDateTime::currentDateTime().addSecs(120).toMSecsSinceEpoch());
-    m_timeout = timeoutTime - QDateTime::currentMSecsSinceEpoch();
+    auto timeoutTime = std::min(event.timestamp().addSecs(600),
+                                QDateTime::currentDateTime().addSecs(120));
+    m_timeout =
+        timeoutTime.toMSecsSinceEpoch() - QDateTime::currentMSecsSinceEpoch();
     if (m_timeout <= 5000) {
         return;
     }
diff --git a/lib/logging.h b/lib/logging.h
index fc0a4c99..1fafa04b 100644
--- a/lib/logging.h
+++ b/lib/logging.h
@@ -44,12 +44,7 @@ inline QDebug formatJson(QDebug debug_object)
 //! Suppress full qualification of enums/QFlags when logging
 inline QDebug terse(QDebug dbg)
 {
-    return
-#if QT_VERSION < QT_VERSION_CHECK(5, 13, 0)
-        dbg.setVerbosity(0), dbg;
-#else
-        dbg.verbosity(QDebug::MinimumVerbosity);
-#endif
+    return dbg.verbosity(QDebug::MinimumVerbosity);
 }
 
 inline qint64 profilerMinNsecs()
@@ -74,15 +69,13 @@ inline qint64 profilerMinNsecs()
  */
 inline QDebug operator<<(QDebug debug_object, Quotient::QDebugManip qdm)
 {
-    return qdm(debug_object);
+    return qdm(debug_object); // NOLINT(performance-unnecessary-value-param)
 }
 
-inline QDebug operator<<(QDebug debug_object, const QElapsedTimer& et)
+inline QDebug operator<<(QDebug debug_object, QElapsedTimer et)
 {
-    auto val = et.nsecsElapsed() / 1000;
-    if (val < 1000)
-        debug_object << val << "µs";
-    else
-        debug_object << val / 1000 << "ms";
+    // NOLINTNEXTLINE(bugprone-integer-division)
+    debug_object << static_cast<double>(et.nsecsElapsed() / 1000) / 1000
+                 << "ms"; // Show in ms with 3 decimal digits precision
     return debug_object;
 }
diff --git a/lib/mxcreply.cpp b/lib/mxcreply.cpp
index b757bb93..c7547be8 100644
--- a/lib/mxcreply.cpp
+++ b/lib/mxcreply.cpp
@@ -5,11 +5,10 @@
 
 #include <QtCore/QBuffer>
 #include "accountregistry.h"
-#include "connection.h"
 #include "room.h"
 
 #ifdef Quotient_E2EE_ENABLED
-#include "events/encryptedfile.h"
+#include "events/filesourceinfo.h"
 #endif
 
 using namespace Quotient;
@@ -21,7 +20,7 @@ public:
         : m_reply(r)
     {}
     QNetworkReply* m_reply;
-    Omittable<EncryptedFile> m_encryptedFile;
+    Omittable<EncryptedFileMetadata> m_encryptedFile;
     QIODevice* m_device = nullptr;
 };
 
@@ -48,9 +47,9 @@ MxcReply::MxcReply(QNetworkReply* reply, Room* room, const QString &eventId)
         if(!d->m_encryptedFile.has_value()) {
             d->m_device = d->m_reply;
         } else {
-            EncryptedFile file = *d->m_encryptedFile;
             auto buffer = new QBuffer(this);
-            buffer->setData(file.decryptFile(d->m_reply->readAll()));
+            buffer->setData(
+                decryptFile(d->m_reply->readAll(), *d->m_encryptedFile));
             buffer->open(ReadOnly);
             d->m_device = buffer;
         }
@@ -65,17 +64,13 @@ MxcReply::MxcReply(QNetworkReply* reply, Room* room, const QString &eventId)
     auto eventIt = room->findInTimeline(eventId);
     if(eventIt != room->historyEdge()) {
         auto event = eventIt->viewAs<RoomMessageEvent>();
-        d->m_encryptedFile = event->content()->fileInfo()->file;
+        if (auto* efm = std::get_if<EncryptedFileMetadata>(
+                &event->content()->fileInfo()->source))
+            d->m_encryptedFile = *efm;
     }
 #endif
 }
 
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
-#define ERROR_SIGNAL errorOccurred
-#else
-#define ERROR_SIGNAL error
-#endif
-
 MxcReply::MxcReply()
     : d(ZeroImpl<Private>())
 {
@@ -87,7 +82,7 @@ MxcReply::MxcReply()
             setError(QNetworkReply::ProtocolInvalidOperationError,
                      BadRequestPhrase);
             setFinished(true);
-            emit ERROR_SIGNAL(QNetworkReply::ProtocolInvalidOperationError);
+            emit errorOccurred(QNetworkReply::ProtocolInvalidOperationError);
             emit finished();
         }, Qt::QueuedConnection);
 }
diff --git a/lib/networkaccessmanager.cpp b/lib/networkaccessmanager.cpp
index f4e7b1af..38ab07cc 100644
--- a/lib/networkaccessmanager.cpp
+++ b/lib/networkaccessmanager.cpp
@@ -68,24 +68,11 @@ void NetworkAccessManager::clearIgnoredSslErrors()
     d->ignoredSslErrors.clear();
 }
 
-static NetworkAccessManager* createNam()
-{
-    auto nam = new NetworkAccessManager();
-#if (QT_VERSION < QT_VERSION_CHECK(5, 15, 0))
-    // See #109; in newer Qt, bearer management is deprecated altogether
-    NetworkAccessManager::connect(nam,
-        &QNetworkAccessManager::networkAccessibleChanged, [nam] {
-            nam->setNetworkAccessible(QNetworkAccessManager::Accessible);
-        });
-#endif
-    return nam;
-}
-
 NetworkAccessManager* NetworkAccessManager::instance()
 {
     static QThreadStorage<NetworkAccessManager*> storage;
     if(!storage.hasLocalData()) {
-        storage.setLocalData(createNam());
+        storage.setLocalData(new NetworkAccessManager());
     }
     return storage.localData();
 }
diff --git a/lib/qt_connection_util.h b/lib/qt_connection_util.h
index 86593cc8..ef7f6f80 100644
--- a/lib/qt_connection_util.h
+++ b/lib/qt_connection_util.h
@@ -9,101 +9,67 @@
 
 namespace Quotient {
 namespace _impl {
-    template <typename... ArgTs>
-    using decorated_slot_tt =
-        std::function<void(QMetaObject::Connection&, const ArgTs&...)>;
+    enum ConnectionType { SingleShot, Until };
 
-    template <typename SenderT, typename SignalT, typename ContextT, typename... ArgTs>
-    inline QMetaObject::Connection
-    connectDecorated(SenderT* sender, SignalT signal, ContextT* context,
-                     decorated_slot_tt<ArgTs...> decoratedSlot,
-                     Qt::ConnectionType connType)
+    template <ConnectionType CType>
+    inline auto connect(auto* sender, auto signal, auto* context, auto slotLike,
+                        Qt::ConnectionType connType)
     {
-        auto pc = std::make_unique<QMetaObject::Connection>();
-        auto& c = *pc; // Resolve a reference before pc is moved to lambda
-
-        // Perfect forwarding doesn't work through signal-slot connections -
-        // arguments are always copied (at best - COWed) to the context of
-        // the slot. Therefore the slot decorator receives const ArgTs&...
-        // rather than ArgTs&&...
-        // TODO (C++20): std::bind_front() instead of lambda.
-        c = QObject::connect(sender, signal, context,
-            [pc = std::move(pc),
-             decoratedSlot = std::move(decoratedSlot)](const ArgTs&... args) {
-                Q_ASSERT(*pc); // If it's been triggered, it should exist
-                decoratedSlot(*pc, args...);
+        auto pConn = std::make_unique<QMetaObject::Connection>();
+        auto& c = *pConn; // Save the reference before pConn is moved from
+        c = QObject::connect(
+            sender, signal, context,
+            [slotLike, pConn = std::move(pConn)](const auto&... args)
+            // The requires-expression below is necessary to prevent Qt
+            // from eagerly trying to fill the lambda with more arguments
+            // than slotLike() (i.e., the original slot) can handle
+            requires requires { slotLike(args...); } {
+                static_assert(CType == Until || CType == SingleShot,
+                              "Unsupported disconnection type");
+                if constexpr (CType == SingleShot) {
+                    // Disconnect early to avoid re-triggers during slotLike()
+                    QObject::disconnect(*pConn);
+                    // Qt kindly keeps slot objects until they do their job,
+                    // even if they disconnect themselves in the process (see
+                    // how doActivate() in qobject.cpp handles c->slotObj).
+                    slotLike(args...);
+                } else if constexpr (CType == Until) {
+                    if (slotLike(args...))
+                        QObject::disconnect(*pConn);
+                }
             },
             connType);
         return c;
     }
-    template <typename SenderT, typename SignalT, typename ContextT,
-              typename... ArgTs>
-    inline QMetaObject::Connection
-    connectUntil(SenderT* sender, SignalT signal, ContextT* context,
-                 std::function<bool(ArgTs...)> functor,
-                 Qt::ConnectionType connType)
-    {
-        return connectDecorated(sender, signal, context,
-            decorated_slot_tt<ArgTs...>(
-                [functor = std::move(functor)](QMetaObject::Connection& c,
-                                               const ArgTs&... args) {
-                    if (functor(args...))
-                        QObject::disconnect(c);
-                }),
-            connType);
-    }
-    template <typename SenderT, typename SignalT, typename ContextT,
-              typename... ArgTs>
-    inline QMetaObject::Connection
-    connectSingleShot(SenderT* sender, SignalT signal, ContextT* context,
-                      std::function<void(ArgTs...)> slot,
-                      Qt::ConnectionType connType)
-    {
-        return connectDecorated(sender, signal, context,
-            decorated_slot_tt<ArgTs...>(
-                [slot = std::move(slot)](QMetaObject::Connection& c,
-                                         const ArgTs&... args) {
-                    QObject::disconnect(c);
-                    slot(args...);
-                }),
-            connType);
-    }
 
-    // TODO: get rid of it as soon as Apple Clang gets proper deduction guides
-    //       for std::function<>
-    //       ...or consider using QtPrivate magic used by QObject::connect()
-    //       ...for inspiration, also check a possible std::not_fn implementation
-    //       at https://en.cppreference.com/w/cpp/utility/functional/not_fn
-    template <typename FnT>
-    inline auto wrap_in_function(FnT&& f)
-    {
-        return typename function_traits<FnT>::function_type(std::forward<FnT>(f));
-    }
+    template <typename SlotT, typename ReceiverT>
+    concept PmfSlot =
+        (fn_arg_count_v<SlotT> > 0
+         && std::is_base_of_v<std::decay_t<fn_arg_t<SlotT, 0>>, ReceiverT>);
 } // namespace _impl
 
-/*! \brief Create a connection that self-disconnects when its "slot" returns true
- *
- *  A slot accepted by connectUntil() is different from classic Qt slots
- * in that its return value must be bool, not void. The slot's return value
- * controls whether the connection should be kept; if the slot returns false,
- * the connection remains; upon returning true, the slot is disconnected from
- * the signal. Because of a different slot signature connectUntil() doesn't
- * accept member functions as QObject::connect or Quotient::connectSingleShot
- * do; you should pass a lambda or a pre-bound member function to it.
- */
-template <typename SenderT, typename SignalT, typename ContextT, typename FunctorT>
-inline auto connectUntil(SenderT* sender, SignalT signal, ContextT* context,
-                         const FunctorT& slot,
+//! \brief Create a connection that self-disconnects when its slot returns true
+//!
+//! A slot accepted by connectUntil() is different from classic Qt slots
+//! in that its return value must be bool, not void. Because of that different
+//! signature connectUntil() doesn't accept member functions in the way
+//! QObject::connect or Quotient::connectSingleShot do; you should pass a lambda
+//! or a pre-bound member function to it.
+//! \return whether the connection should be dropped; false means that the
+//!         connection remains; upon returning true, the slot is disconnected
+//!         from the signal.
+inline auto connectUntil(auto* sender, auto signal, auto* context,
+                         auto smartSlot,
                          Qt::ConnectionType connType = Qt::AutoConnection)
 {
-    return _impl::connectUntil(sender, signal, context, _impl::wrap_in_function(slot),
-                               connType);
+    return _impl::connect<_impl::Until>(sender, signal, context, smartSlot,
+                                        connType);
 }
 
-/// Create a connection that self-disconnects after triggering on the signal
-template <typename SenderT, typename SignalT, typename ContextT, typename FunctorT>
-inline auto connectSingleShot(SenderT* sender, SignalT signal,
-                              ContextT* context, const FunctorT& slot,
+//! Create a connection that self-disconnects after triggering on the signal
+template <typename ContextT, typename SlotT>
+inline auto connectSingleShot(auto* sender, auto signal, ContextT* context,
+                              SlotT slot,
                               Qt::ConnectionType connType = Qt::AutoConnection)
 {
 #if QT_VERSION_MAJOR >= 6
@@ -111,25 +77,26 @@ inline auto connectSingleShot(SenderT* sender, SignalT signal,
                             Qt::ConnectionType(connType
                                                | Qt::SingleShotConnection));
 #else
-    return _impl::connectSingleShot(
-        sender, signal, context, _impl::wrap_in_function(slot), connType);
-}
-
-// Specialisation for usual Qt slots passed as pointers-to-members.
-template <typename SenderT, typename SignalT, typename ReceiverT,
-          typename SlotObjectT, typename... ArgTs>
-inline auto connectSingleShot(SenderT* sender, SignalT signal,
-                              ReceiverT* receiver,
-                              void (SlotObjectT::*slot)(ArgTs...),
-                              Qt::ConnectionType connType = Qt::AutoConnection)
-{
-    // TODO: when switching to C++20, use std::bind_front() instead
-    return _impl::connectSingleShot(sender, signal, receiver,
-                                    _impl::wrap_in_function(
-                                        [receiver, slot](const ArgTs&... args) {
-                                            (receiver->*slot)(args...);
-                                        }),
-                                    connType);
+    // In case of classic Qt pointer-to-member-function slots the receiver
+    // object has to be pre-bound to the slot to make it self-contained
+    if constexpr (_impl::PmfSlot<SlotT, ContextT>) {
+        auto&& boundSlot =
+#    if __cpp_lib_bind_front // Needs Apple Clang 13 (other platforms are fine)
+            std::bind_front(slot, context);
+#    else
+            [context, slot](const auto&... args)
+            requires requires { (context->*slot)(args...); }
+            {
+                (context->*slot)(args...);
+            };
+#    endif
+        return _impl::connect<_impl::SingleShot>(
+            sender, signal, context,
+            std::forward<decltype(boundSlot)>(boundSlot), connType);
+    } else {
+        return _impl::connect<_impl::SingleShot>(sender, signal, context, slot,
+                                                 connType);
+    }
 #endif
 }
 
diff --git a/lib/quotient_common.h b/lib/quotient_common.h
index 2b785a39..7fec9274 100644
--- a/lib/quotient_common.h
+++ b/lib/quotient_common.h
@@ -41,44 +41,8 @@
     Q_ENUM_NS_IMPL(Enum)                  \
     Q_FLAG_NS(Flags)
 
-// Apple Clang hasn't caught up with explicit(bool) yet
-#if __cpp_conditional_explicit >= 201806L
-#define QUO_IMPLICIT explicit(false)
-#else
-#define QUO_IMPLICIT
-#endif
-
-#define DECL_DEPRECATED_ENUMERATOR(Deprecated, Recommended) \
-    Deprecated Q_DECL_ENUMERATOR_DEPRECATED_X("Use " #Recommended) = Recommended
-
-#if QT_VERSION < QT_VERSION_CHECK(5, 14, 0)
-// The first line forward-declares the namespace static metaobject with
-// QUOTIENT_API so that dynamically linked clients could serialise flag/enum
-// values from the namespace; Qt before 5.14 doesn't help with that. The second
-// line is needed for moc to do its job on the namespace.
-#define QUO_NAMESPACE \
-    extern QUOTIENT_API const QMetaObject staticMetaObject; \
-    Q_NAMESPACE
-#else
-// Since Qt 5.14.0, it's all packed in a single macro
-#define QUO_NAMESPACE Q_NAMESPACE_EXPORT(QUOTIENT_API)
-#endif
-
 namespace Quotient {
-QUO_NAMESPACE
-
-// std::array {} needs explicit template parameters on macOS because
-// Apple stdlib doesn't have deduction guides for std::array. C++20 has
-// to_array() but that can't be borrowed, this time because of MSVC:
-// https://developercommunity.visualstudio.com/t/vc-ice-p1-initc-line-3652-from-stdto-array/1464038
-// Therefore a simpler (but also slightly more wobbly - it resolves the element
-// type using std::common_type<>) make_array facility is implemented here.
-template <typename... Ts>
-constexpr auto make_array(Ts&&... items)
-{
-    return std::array<std::common_type_t<Ts...>, sizeof...(items)>(
-        { std::forward<Ts>(items)... });
-}
+Q_NAMESPACE_EXPORT(QUOTIENT_API)
 
 // TODO: code like this should be generated from the CS API definition
 
@@ -87,7 +51,7 @@ constexpr auto make_array(Ts&&... items)
 //! These are used for member events. The names here are case-insensitively
 //! equal to state names used on the wire.
 //! \sa MemberEventContent, RoomMemberEvent
-enum class Membership : unsigned int {
+enum class Membership : uint16_t {
     // Specific power-of-2 values (1,2,4,...) are important here as syncdata.cpp
     // depends on that, as well as Join being the first in line
     Invalid = 0x0,
@@ -100,9 +64,10 @@ enum class Membership : unsigned int {
 };
 QUO_DECLARE_FLAGS_NS(MembershipMask, Membership)
 
-constexpr auto MembershipStrings = make_array(
-    // The order MUST be the same as the order in the original enum
-    "join", "leave", "invite", "knock", "ban");
+constexpr std::array MembershipStrings {
+    // The order MUST be the same as the order in the Membership enum
+    "join", "leave", "invite", "knock", "ban"
+};
 
 //! \brief Local user join-state names
 //!
@@ -118,10 +83,10 @@ enum class JoinState : std::underlying_type_t<Membership> {
 };
 QUO_DECLARE_FLAGS_NS(JoinStates, JoinState)
 
-[[maybe_unused]] constexpr auto JoinStateStrings = make_array(
+[[maybe_unused]] constexpr std::array JoinStateStrings {
     MembershipStrings[0], MembershipStrings[1], MembershipStrings[2],
     MembershipStrings[3] /* same as MembershipStrings, sans "ban" */
-);
+};
 
 //! \brief Network job running policy flags
 //!
@@ -132,7 +97,7 @@ Q_ENUM_NS(RunningPolicy)
 
 //! \brief The result of URI resolution using UriResolver
 //! \sa UriResolver
-enum UriResolveResult : short {
+enum UriResolveResult : int8_t {
     StillResolving = -1,
     UriResolved = 0,
     CouldNotResolve,
@@ -142,13 +107,19 @@ enum UriResolveResult : short {
 };
 Q_ENUM_NS(UriResolveResult)
 
-enum RoomType {
-    Space,
-    Undefined,
+enum class RoomType : uint8_t {
+    Space = 0,
+    Undefined = 0xFF,
 };
 Q_ENUM_NS(RoomType)
 
-[[maybe_unused]] constexpr auto RoomTypeStrings = make_array("m.space");
+[[maybe_unused]] constexpr std::array RoomTypeStrings { "m.space" };
+
+enum class EncryptionType : uint8_t {
+    MegolmV1AesSha2 = 0,
+    Undefined = 0xFF,
+};
+Q_ENUM_NS(EncryptionType)
 
 } // namespace Quotient
 Q_DECLARE_OPERATORS_FOR_FLAGS(Quotient::MembershipMask)
diff --git a/lib/room.cpp b/lib/room.cpp
index a423e04f..3ee81dcc 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -12,7 +12,6 @@
 #include "avatar.h"
 #include "connection.h"
 #include "converters.h"
-#include "e2ee/qolmoutboundsession.h"
 #include "syncdata.h"
 #include "user.h"
 #include "eventstats.h"
@@ -118,7 +117,7 @@ public:
     // A map from evtId to a map of relation type to a vector of event
     // pointers. Not using QMultiHash, because we want to quickly return
     // a number of relations for a given event without enumerating them.
-    QHash<QPair<QString, QString>, RelatedEvents> relations;
+    QHash<std::pair<QString, QString>, RelatedEvents> relations;
     QString displayname;
     Avatar avatar;
     QHash<QString, Notification> notifications;
@@ -219,8 +218,9 @@ public:
                 // In the absence of a real event, make a stub as-if an event
                 // with empty content has been received. Event classes should be
                 // prepared for empty/invalid/malicious content anyway.
-                stubbedState.emplace(evtKey, loadStateEvent(evtKey.first, {},
-                                                            evtKey.second));
+                stubbedState.emplace(evtKey,
+                                     loadEvent<StateEventBase>(evtKey.first,
+                                                               evtKey.second));
                 qCDebug(STATE) << "A new stub event created for key {"
                                << evtKey.first << evtKey.second << "}";
                 qCDebug(STATE) << "Stubbed state size:" << stubbedState.size();
@@ -277,10 +277,17 @@ public:
      * Remove events from the passed container that are already in the timeline
      */
     void dropDuplicateEvents(RoomEvents& events) const;
-
-    Changes setLastReadReceipt(const QString& userId, rev_iter_t newMarker,
-                               ReadReceipt newReceipt = {},
-                               bool deferStatsUpdate = false);
+    void decryptIncomingEvents(RoomEvents& events);
+
+    //! \brief update last receipt record for a given user
+    //!
+    //! \return previous event id of the receipt if the new receipt changed
+    //!         it, or `none` if no change took place
+    Omittable<QString> setLastReadReceipt(const QString& userId, rev_iter_t newMarker,
+                               ReadReceipt newReceipt = {});
+    Changes setLocalLastReadReceipt(const rev_iter_t& newMarker,
+                                    ReadReceipt newReceipt = {},
+                                    bool deferStatsUpdate = false);
     Changes setFullyReadMarker(const QString &eventId);
     Changes updateStats(const rev_iter_t& from, const rev_iter_t& to);
     bool markMessagesAsRead(const rev_iter_t& upToMarker);
@@ -340,17 +347,21 @@ public:
 
 #ifdef Quotient_E2EE_ENABLED
     UnorderedMap<QString, QOlmInboundGroupSessionPtr> groupSessions;
-
+    int currentMegolmSessionMessageCount = 0;
+    //TODO save this to database
+    unsigned long long currentMegolmSessionCreationTimestamp = 0;
     QOlmOutboundGroupSessionPtr currentOutboundMegolmSession = nullptr;
 
-    bool addInboundGroupSession(QString sessionId, QString sessionKey, const QString& senderId, const QString& olmSessionId)
+    bool addInboundGroupSession(QString sessionId, QByteArray sessionKey,
+                                const QString& senderId,
+                                const QString& olmSessionId)
     {
-        if (groupSessions.find(sessionId) != groupSessions.end()) {
+        if (groupSessions.contains(sessionId)) {
             qCWarning(E2EE) << "Inbound Megolm session" << sessionId << "already exists";
             return false;
         }
 
-        auto megolmSession = QOlmInboundGroupSession::create(sessionKey.toLatin1());
+        auto megolmSession = QOlmInboundGroupSession::create(sessionKey);
         if (megolmSession->sessionId() != sessionId) {
             qCWarning(E2EE) << "Session ID mismatch in m.room_key event";
             return false;
@@ -358,13 +369,12 @@ public:
         megolmSession->setSenderId(senderId);
         megolmSession->setOlmSessionId(olmSessionId);
         qCWarning(E2EE) << "Adding inbound session";
-        connection->saveMegolmSession(q, megolmSession.get());
+        connection->saveMegolmSession(q, *megolmSession);
         groupSessions[sessionId] = std::move(megolmSession);
         return true;
     }
 
     QString groupSessionDecryptMessage(QByteArray cipher,
-                                       const QString& senderKey,
                                        const QString& sessionId,
                                        const QString& eventId,
                                        QDateTime timestamp,
@@ -375,7 +385,7 @@ public:
             // qCWarning(E2EE) << "Unable to decrypt event" << eventId
             //               << "The sender's device has not sent us the keys for "
             //                  "this message";
-            return QString();
+            return {};
         }
         auto& senderSession = groupSessionIt->second;
         if (senderSession->senderId() != senderId) {
@@ -383,19 +393,24 @@ public:
             return {};
         }
         auto decryptResult = senderSession->decrypt(cipher);
-        if(std::holds_alternative<QOlmError>(decryptResult)) {
+        if(!decryptResult) {
             qCWarning(E2EE) << "Unable to decrypt event" << eventId
-            << "with matching megolm session:" << std::get<QOlmError>(decryptResult);
-            return QString();
+            << "with matching megolm session:" << decryptResult.error();
+            return {};
         }
-        const auto& [content, index] = std::get<std::pair<QString, uint32_t>>(decryptResult);
-        const auto& [recordEventId, ts] = q->connection()->database()->groupSessionIndexRecord(q->id(), senderSession->sessionId(), index);
+        const auto& [content, index] = *decryptResult;
+        const auto& [recordEventId, ts] =
+            q->connection()->database()->groupSessionIndexRecord(
+                q->id(), senderSession->sessionId(), index);
         if (recordEventId.isEmpty()) {
-            q->connection()->database()->addGroupSessionIndexRecord(q->id(), senderSession->sessionId(), index, eventId, timestamp.toMSecsSinceEpoch());
+            q->connection()->database()->addGroupSessionIndexRecord(
+                q->id(), senderSession->sessionId(), index, eventId,
+                timestamp.toMSecsSinceEpoch());
         } else {
-            if ((eventId != recordEventId) || (ts != timestamp.toMSecsSinceEpoch())) {
+            if ((eventId != recordEventId)
+                || (ts != timestamp.toMSecsSinceEpoch())) {
                 qCWarning(E2EE) << "Detected a replay attack on event" << eventId;
-                return QString();
+                return {};
             }
         }
         return content;
@@ -403,10 +418,17 @@ public:
 
     bool shouldRotateMegolmSession() const
     {
-        if (!q->usesEncryption()) {
+        const auto* encryptionConfig = currentState.get<EncryptionEvent>();
+        if (!encryptionConfig || !encryptionConfig->useEncryption())
             return false;
-        }
-        return currentOutboundMegolmSession->messageCount() >= rotationMessageCount() || currentOutboundMegolmSession->creationTime().addMSecs(rotationInterval()) < QDateTime::currentDateTime();
+
+        const auto rotationInterval = encryptionConfig->rotationPeriodMs();
+        const auto rotationMessageCount = encryptionConfig->rotationPeriodMsgs();
+        return currentOutboundMegolmSession->messageCount()
+                   >= rotationMessageCount
+               || currentOutboundMegolmSession->creationTime().addMSecs(
+                      rotationInterval)
+                      < QDateTime::currentDateTime();
     }
 
     bool hasValidMegolmSession() const
@@ -417,137 +439,45 @@ public:
         return currentOutboundMegolmSession != nullptr;
     }
 
-    /// Time in milliseconds after which the outgoing megolmsession should be replaced
-    unsigned int rotationInterval() const
-    {
-        if (!q->usesEncryption()) {
-            return 0;
-        }
-        return q->getCurrentState<EncryptionEvent>()->rotationPeriodMs();
-    }
-
-    // Number of messages sent by this user after which the outgoing megolm session should be replaced
-    int rotationMessageCount() const
-    {
-        if (!q->usesEncryption()) {
-            return 0;
-        }
-        return q->getCurrentState<EncryptionEvent>()->rotationPeriodMsgs();
-    }
     void createMegolmSession() {
-        qCDebug(E2EE) << "Creating new outbound megolm session for room " << q->id();
+        qCDebug(E2EE) << "Creating new outbound megolm session for room "
+                      << q->objectName();
         currentOutboundMegolmSession = QOlmOutboundGroupSession::create();
-        connection->saveCurrentOutboundMegolmSession(q, currentOutboundMegolmSession);
+        connection->saveCurrentOutboundMegolmSession(
+            id, *currentOutboundMegolmSession);
 
         const auto sessionKey = currentOutboundMegolmSession->sessionKey();
-        if(std::holds_alternative<QOlmError>(sessionKey)) {
+        if(!sessionKey) {
             qCWarning(E2EE) << "Failed to load key for new megolm session";
             return;
         }
-        addInboundGroupSession(currentOutboundMegolmSession->sessionId(), std::get<QByteArray>(sessionKey), q->localUser()->id(), "SELF"_ls);
+        addInboundGroupSession(currentOutboundMegolmSession->sessionId(), *sessionKey, q->localUser()->id(), "SELF"_ls);
     }
 
-    std::unique_ptr<EncryptedEvent> payloadForUserDevice(User* user, const QString& device, const QByteArray& sessionId, const QByteArray& sessionKey)
+    QMultiHash<QString, QString> getDevicesWithoutKey() const
     {
-        // Noisy but nice for debugging
-        //qCDebug(E2EE) << "Creating the payload for" << user->id() << device << sessionId << sessionKey.toHex();
-        const auto event = makeEvent<RoomKeyEvent>("m.megolm.v1.aes-sha2", q->id(), sessionId, sessionKey, q->localUser()->id());
-        QJsonObject payloadJson = event->fullJson();
-        payloadJson["recipient"] = user->id();
-        payloadJson["sender"] = connection->user()->id();
-        QJsonObject recipientObject;
-        recipientObject["ed25519"] = connection->edKeyForUserDevice(user->id(), device);
-        payloadJson["recipient_keys"] = recipientObject;
-        QJsonObject senderObject;
-        senderObject["ed25519"] = QString(connection->olmAccount()->identityKeys().ed25519);
-        payloadJson["keys"] = senderObject;
-        payloadJson["sender_device"] = connection->deviceId();
-        auto cipherText = connection->olmEncryptMessage(user, device, QJsonDocument(payloadJson).toJson(QJsonDocument::Compact));
-        QJsonObject encrypted;
-        encrypted[connection->curveKeyForUserDevice(user->id(), device)] = QJsonObject{{"type", cipherText.first}, {"body", QString(cipherText.second)}};
-
-        return makeEvent<EncryptedEvent>(encrypted, connection->olmAccount()->identityKeys().curve25519);
-    }
-
-    QHash<User*, QStringList> getDevicesWithoutKey() const
-    {
-        QHash<User*, QStringList> devices;
-        auto rawDevices = q->connection()->database()->devicesWithoutKey(q, QString(currentOutboundMegolmSession->sessionId()));
-        for (const auto& user : rawDevices.keys()) {
-            devices[q->connection()->user(user)] = rawDevices[user];
-        }
-        return devices;
-    }
+        QMultiHash<QString, QString> devices;
+        for (const auto& user : q->users())
+            for (const auto& deviceId : connection->devicesForUser(user->id()))
+                devices.insert(user->id(), deviceId);
 
-    void sendRoomKeyToDevices(const QByteArray& sessionId, const QByteArray& sessionKey, const QHash<User*, QStringList> devices, int index)
-    {
-        qCDebug(E2EE) << "Sending room key to devices" << sessionId, sessionKey.toHex();
-        QHash<QString, QHash<QString, QString>> hash;
-        for (const auto& user : devices.keys()) {
-            QHash<QString, QString> u;
-            for(const auto &device : devices[user]) {
-                if (!connection->hasOlmSession(user, device)) {
-                    u[device] = "signed_curve25519"_ls;
-                    qCDebug(E2EE) << "Adding" << user << device << "to keys to claim";
-                }
-            }
-            if (!u.isEmpty()) {
-                hash[user->id()] = u;
-            }
-        }
-        if (hash.isEmpty()) {
-            return;
-        }
-        auto job = connection->callApi<ClaimKeysJob>(hash);
-        connect(job, &BaseJob::success, q, [job, this, sessionId, sessionKey, devices, index](){
-            Connection::UsersToDevicesToEvents usersToDevicesToEvents;
-            const auto data = job->jsonData();
-            for(const auto &user : devices.keys()) {
-                for(const auto &device : devices[user]) {
-                    const auto recipientCurveKey = connection->curveKeyForUserDevice(user->id(), device);
-                    if (!connection->hasOlmSession(user, device)) {
-                        qCDebug(E2EE) << "Creating a new session for" << user << device;
-                        if(data["one_time_keys"][user->id()][device].toObject().isEmpty()) {
-                            qWarning() << "No one time key for" << user << device;
-                            continue;
-                        }
-                        const auto keyId = data["one_time_keys"][user->id()][device].toObject().keys()[0];
-                        const auto oneTimeKey = data["one_time_keys"][user->id()][device][keyId]["key"].toString();
-                        const auto signature = data["one_time_keys"][user->id()][device][keyId]["signatures"][user->id()][QStringLiteral("ed25519:") + device].toString().toLatin1();
-                        auto signedData = data["one_time_keys"][user->id()][device][keyId].toObject();
-                        signedData.remove("unsigned");
-                        signedData.remove("signatures");
-                        auto signatureMatch = QOlmUtility().ed25519Verify(connection->edKeyForUserDevice(user->id(), device).toLatin1(), QJsonDocument(signedData).toJson(QJsonDocument::Compact), signature);
-                        if (std::holds_alternative<QOlmError>(signatureMatch)) {
-                            qCWarning(E2EE) << "Failed to verify one-time-key signature for" << user->id() << device << ". Skipping this device.";
-                            continue;
-                        } else {
-                        }
-                        connection->createOlmSession(recipientCurveKey, oneTimeKey);
-                    }
-                    usersToDevicesToEvents[user->id()][device] = payloadForUserDevice(user, device, sessionId, sessionKey);
-                }
-            }
-            if (!usersToDevicesToEvents.empty()) {
-                connection->sendToDevices("m.room.encrypted", usersToDevicesToEvents);
-                connection->database()->setDevicesReceivedKey(q->id(), devices, sessionId, index);
-            }
-        });
+        return connection->database()->devicesWithoutKey(
+            id, devices, currentOutboundMegolmSession->sessionId());
     }
 
-    void sendMegolmSession(const QHash<User *, QStringList>& devices) {
+    void sendMegolmSession(const QMultiHash<QString, QString>& devices) const {
         // Save the session to this device
         const auto sessionId = currentOutboundMegolmSession->sessionId();
-        const auto _sessionKey = currentOutboundMegolmSession->sessionKey();
-        if(std::holds_alternative<QOlmError>(_sessionKey)) {
+        const auto sessionKey = currentOutboundMegolmSession->sessionKey();
+        if(!sessionKey) {
             qCWarning(E2EE) << "Error loading session key";
             return;
         }
-        const auto sessionKey = std::get<QByteArray>(_sessionKey);
-        const auto senderKey = q->connection()->olmAccount()->identityKeys().curve25519;
 
         // Send the session to other people
-        sendRoomKeyToDevices(sessionId, sessionKey, devices, currentOutboundMegolmSession->sessionMessageIndex());
+        connection->sendSessionKeyToDevices(
+            id, sessionId, *sessionKey, devices,
+            currentOutboundMegolmSession->sessionMessageIndex());
     }
 
 #endif // Quotient_E2EE_ENABLED
@@ -569,11 +499,6 @@ Room::Room(Connection* connection, QString id, JoinState initialJoinState)
     // https://marcmutz.wordpress.com/translated-articles/pimp-my-pimpl-%E2%80%94-reloaded/
     d->q = this;
     d->displayname = d->calculateDisplayname(); // Set initial "Empty room" name
-    connectUntil(connection, &Connection::loadedRoomState, this, [this](Room* r) {
-        if (this == r)
-            emit baseStateLoaded();
-        return this == r; // loadedRoomState fires only once per room
-    });
 #ifdef Quotient_E2EE_ENABLED
     connectSingleShot(this, &Room::encryption, this, [this, connection](){
         connection->encryptionUpdate(this);
@@ -584,7 +509,8 @@ Room::Room(Connection* connection, QString id, JoinState initialJoinState)
         }
     });
     d->groupSessions = connection->loadRoomMegolmSessions(this);
-    d->currentOutboundMegolmSession = connection->loadCurrentOutboundMegolmSession(this);
+    d->currentOutboundMegolmSession =
+        connection->loadCurrentOutboundMegolmSession(this->id());
     if (d->shouldRotateMegolmSession()) {
         d->currentOutboundMegolmSession = nullptr;
     }
@@ -592,7 +518,9 @@ Room::Room(Connection* connection, QString id, JoinState initialJoinState)
         if (!usesEncryption()) {
             return;
         }
-        d->currentOutboundMegolmSession = nullptr;
+        if (d->hasValidMegolmSession()) {
+            d->createMegolmSession();
+        }
         qCDebug(E2EE) << "Invalidating current megolm session because user left";
 
     });
@@ -779,10 +707,9 @@ void Room::setJoinState(JoinState state)
     emit joinStateChanged(oldState, state);
 }
 
-Room::Changes Room::Private::setLastReadReceipt(const QString& userId,
-                                                rev_iter_t newMarker,
-                                                ReadReceipt newReceipt,
-                                                bool deferStatsUpdate)
+Omittable<QString> Room::Private::setLastReadReceipt(const QString& userId,
+                                                     rev_iter_t newMarker,
+                                                     ReadReceipt newReceipt)
 {
     if (newMarker == historyEdge() && !newReceipt.eventId.isEmpty())
         newMarker = q->findInTimeline(newReceipt.eventId);
@@ -796,7 +723,7 @@ Room::Changes Room::Private::setLastReadReceipt(const QString& userId,
         // eagerMarker is now just after the desired event for newMarker
         if (eagerMarker != newMarker.base()) {
             newMarker = rev_iter_t(eagerMarker);
-            qCDebug(EPHEMERAL) << "Auto-promoted read receipt for" << userId
+            qDebug(EPHEMERAL) << "Auto-promoted read receipt for" << userId
                                << "to" << *newMarker;
         }
         // Fill newReceipt with the event (and, if needed, timestamp) from
@@ -810,14 +737,19 @@ Room::Changes Room::Private::setLastReadReceipt(const QString& userId,
     const auto prevEventId = storedReceipt.eventId;
     // Check that either the new marker is actually "newer" than the current one
     // or, if both markers are at historyEdge(), event ids are different.
+    // This logic tackles, in particular, the case when the new event is not
+    // found (most likely, because it's too old and hasn't been fetched from
+    // the server yet) but there is a previous marker for a user; in that case,
+    // the previous marker is kept because read receipts are not supposed
+    // to move backwards. If neither new nor old event is found, the new receipt
+    // is blindly stored, in a hope it's also "newer" in the timeline.
     // NB: with reverse iterators, timeline history edge >= sync edge
     if (prevEventId == newReceipt.eventId
         || newMarker > q->findInTimeline(prevEventId))
-        return Change::None;
+        return {};
 
     // Finally make the change
 
-    Changes changes = Change::Other;
     auto oldEventReadUsersIt =
         eventIdReadUsers.find(prevEventId); // clazy:exclude=detaching-member
     if (oldEventReadUsersIt != eventIdReadUsers.end()) {
@@ -829,7 +761,7 @@ Room::Changes Room::Private::setLastReadReceipt(const QString& userId,
     storedReceipt = move(newReceipt);
 
     {
-        auto dbg = qDebug(EPHEMERAL); // This trick needs qDebug, not qCDebug
+        auto dbg = qDebug(EPHEMERAL); // NB: qCDebug can't be used like that
         dbg << "The new read receipt for" << userId << "is now at";
         if (newMarker == historyEdge())
             dbg << storedReceipt.eventId;
@@ -837,25 +769,37 @@ Room::Changes Room::Private::setLastReadReceipt(const QString& userId,
             dbg << *newMarker;
     }
 
-    // TODO: use Room::member() when it becomes a thing and only emit signals
-    //       for actual members, not just any user
-    const auto member = q->user(userId);
-    Q_ASSERT(member != nullptr);
-    if (isLocalUser(member) && !deferStatsUpdate) {
-        if (unreadStats.updateOnMarkerMove(q, q->findInTimeline(prevEventId),
+    // NB: This method, unlike setLocalLastReadReceipt, doesn't emit
+    // lastReadEventChanged() to avoid numerous emissions when many read
+    // receipts arrive. It can be called thousands of times during an initial
+    // sync, e.g.
+    // TODO: remove in 0.8
+    if (const auto member = q->user(userId); !isLocalUser(member))
+         emit q->readMarkerForUserMoved(member, prevEventId,
+                                        storedReceipt.eventId);
+    return prevEventId;
+}
+
+Room::Changes Room::Private::setLocalLastReadReceipt(const rev_iter_t& newMarker,
+                                                     ReadReceipt newReceipt,
+                                                     bool deferStatsUpdate)
+{
+    auto prevEventId =
+        setLastReadReceipt(connection->userId(), newMarker, move(newReceipt));
+    if (!prevEventId)
+        return Change::None;
+    Changes changes = Change::Other;
+    if (!deferStatsUpdate) {
+        if (unreadStats.updateOnMarkerMove(q, q->findInTimeline(*prevEventId),
                                            newMarker)) {
-            qCDebug(MESSAGES)
+            qDebug(MESSAGES)
                 << "Updated unread event statistics in" << q->objectName()
                 << "after moving the local read receipt:" << unreadStats;
             changes |= Change::UnreadStats;
         }
         Q_ASSERT(unreadStats.isValidFor(q, newMarker)); // post-check
     }
-    emit q->lastReadEventChanged(member);
-    // TODO: remove in 0.8
-    if (!isLocalUser(member))
-        emit q->readMarkerForUserMoved(member, prevEventId,
-                                       storedReceipt.eventId);
+    emit q->lastReadEventChanged({ connection->userId() });
     return changes;
 }
 
@@ -870,7 +814,7 @@ Room::Changes Room::Private::updateStats(const rev_iter_t& from,
     Changes changes = Change::None;
     // Correct the read receipt to never be behind the fully read marker
     if (readReceiptMarker > fullyReadMarker
-        && setLastReadReceipt(connection->userId(), fullyReadMarker, {}, true)) {
+        && setLocalLastReadReceipt(fullyReadMarker, {}, true)) {
         changes |= Change::Other;
         readReceiptMarker = q->localReadReceiptMarker();
         qCInfo(MESSAGES) << "The local m.read receipt was behind m.fully_read "
@@ -968,7 +912,7 @@ Room::Changes Room::Private::setFullyReadMarker(const QString& eventId)
     QT_IGNORE_DEPRECATIONS(Changes changes = Change::ReadMarker|Change::Other;)
     if (const auto rm = q->fullyReadMarker(); rm != historyEdge()) {
         // Pull read receipt if it's behind, and update statistics
-        changes |= setLastReadReceipt(connection->userId(), rm);
+        changes |= setLocalLastReadReceipt(rm);
         if (partiallyReadStats.updateOnMarkerMove(q, prevReadMarker, rm)) {
             changes |= Change::PartiallyReadStats;
             qCDebug(MESSAGES)
@@ -986,9 +930,8 @@ Room::Changes Room::Private::setFullyReadMarker(const QString& eventId)
 
 void Room::setReadReceipt(const QString& atEventId)
 {
-    if (const auto changes = d->setLastReadReceipt(localUser()->id(),
-                                                   historyEdge(),
-                                                   { atEventId })) {
+    if (const auto changes =
+            d->setLocalLastReadReceipt(historyEdge(), { atEventId })) {
         connection()->callApi<PostReceiptJob>(BackgroundRequest, id(),
                                               QStringLiteral("m.read"),
                                               QUrl::toPercentEncoding(atEventId));
@@ -1517,7 +1460,7 @@ QUrl Room::urlToThumbnail(const QString& eventId) const
             auto* thumbnail = event->content()->thumbnailInfo();
             Q_ASSERT(thumbnail != nullptr);
             return connection()->getUrlForApi<MediaThumbnailJob>(
-                thumbnail->url, thumbnail->imageSize);
+                thumbnail->url(), thumbnail->imageSize);
         }
     qCDebug(MAIN) << "Event" << eventId << "has no thumbnail";
     return {};
@@ -1528,7 +1471,7 @@ QUrl Room::urlToDownload(const QString& eventId) const
     if (auto* event = d->getEventWithFile(eventId)) {
         auto* fileInfo = event->content()->fileInfo();
         Q_ASSERT(fileInfo != nullptr);
-        return connection()->getUrlForApi<DownloadFileJob>(fileInfo->url);
+        return connection()->getUrlForApi<DownloadFileJob>(fileInfo->url());
     }
     return {};
 }
@@ -1600,7 +1543,7 @@ QStringList Room::safeMemberNames() const
 {
     QStringList res;
     res.reserve(d->membersMap.size());
-    for (auto u: std::as_const(d->membersMap))
+    for (const auto* u: std::as_const(d->membersMap))
         res.append(safeMemberName(u->id()));
 
     return res;
@@ -1610,7 +1553,7 @@ QStringList Room::htmlSafeMemberNames() const
 {
     QStringList res;
     res.reserve(d->membersMap.size());
-    for (auto u: std::as_const(d->membersMap))
+    for (const auto* u: std::as_const(d->membersMap))
         res.append(htmlSafeMemberName(u->id()));
 
     return res;
@@ -1649,9 +1592,9 @@ RoomEventPtr Room::decryptMessage(const EncryptedEvent& encryptedEvent)
         return {};
     }
     QString decrypted = d->groupSessionDecryptMessage(
-        encryptedEvent.ciphertext(), encryptedEvent.senderKey(),
-        encryptedEvent.sessionId(), encryptedEvent.id(),
-        encryptedEvent.originTimestamp(), encryptedEvent.senderId());
+        encryptedEvent.ciphertext(), encryptedEvent.sessionId(),
+        encryptedEvent.id(), encryptedEvent.originTimestamp(),
+        encryptedEvent.senderId());
     if (decrypted.isEmpty()) {
         // qCWarning(E2EE) << "Encrypted message is empty";
         return {};
@@ -1680,7 +1623,8 @@ void Room::handleRoomKeyEvent(const RoomKeyEvent& roomKeyEvent,
                         << roomKeyEvent.algorithm() << "in m.room_key event";
     }
     if (d->addInboundGroupSession(roomKeyEvent.sessionId(),
-                                  roomKeyEvent.sessionKey(), senderId, olmSessionId)) {
+                                  roomKeyEvent.sessionKey(), senderId,
+                                  olmSessionId)) {
         qCWarning(E2EE) << "added new inboundGroupSession:"
                       << d->groupSessions.size();
         auto undecryptedEvents = d->undecryptedEvents[roomKeyEvent.sessionId()];
@@ -1690,8 +1634,7 @@ void Room::handleRoomKeyEvent(const RoomKeyEvent& roomKeyEvent,
                 continue;
             auto& ti = d->timeline[Timeline::size_type(*pIdx - minTimelineIndex())];
             if (auto encryptedEvent = ti.viewAs<EncryptedEvent>()) {
-                auto decrypted = decryptMessage(*encryptedEvent);
-                if(decrypted) {
+                if (auto decrypted = decryptMessage(*encryptedEvent)) {
                     // The reference will survive the pointer being moved
                     auto& decryptedEvent = *decrypted;
                     auto oldEvent = ti.replaceEvent(std::move(decrypted));
@@ -1986,6 +1929,9 @@ Room::Changes Room::Private::updateStatsFromSyncData(const SyncRoomData& data,
 
 void Room::updateData(SyncRoomData&& data, bool fromCache)
 {
+    qCDebug(MAIN) << "--- Updating room" << id() << "/" << objectName();
+    bool firstUpdate = d->baseState.empty();
+
     if (d->prevBatch.isEmpty())
         d->prevBatch = data.timelinePrevBatch;
     setJoinState(data.joinState);
@@ -2011,6 +1957,9 @@ void Room::updateData(SyncRoomData&& data, bool fromCache)
         emit namesChanged(this);
 
     d->postprocessChanges(roomChanges, !fromCache);
+    if (firstUpdate)
+        emit baseStateLoaded();
+    qCDebug(MAIN) << "--- Finished updating room" << id() << "/" << objectName();
 }
 
 void Room::Private::postprocessChanges(Changes changes, bool saveState)
@@ -2036,11 +1985,8 @@ void Room::Private::postprocessChanges(Changes changes, bool saveState)
     if (changes & Change::Highlights)
         emit q->highlightCountChanged();
 
-    qCDebug(MAIN) << terse << changes << "= hex" <<
-#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
-        Qt::
-#endif
-            hex << uint(changes) << "in" << q->objectName();
+    qCDebug(MAIN) << terse << changes << "= hex" << Qt::hex << uint(changes)
+                  << "in" << q->objectName();
     emit q->changed(changes);
     if (saveState)
         connection->saveRoomState(q);
@@ -2076,6 +2022,7 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent)
     const auto txnId = pEvent->transactionId();
     // TODO, #133: Enqueue the job rather than immediately trigger it.
     const RoomEvent* _event = pEvent;
+    std::unique_ptr<EncryptedEvent> encryptedEvent;
 
     if (q->usesEncryption()) {
 #ifndef Quotient_E2EE_ENABLED
@@ -2085,17 +2032,17 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent)
         if (!hasValidMegolmSession() || shouldRotateMegolmSession()) {
             createMegolmSession();
         }
-        const auto devicesWithoutKey = getDevicesWithoutKey();
-        sendMegolmSession(devicesWithoutKey);
+        sendMegolmSession(getDevicesWithoutKey());
 
         const auto encrypted = currentOutboundMegolmSession->encrypt(QJsonDocument(pEvent->fullJson()).toJson());
         currentOutboundMegolmSession->setMessageCount(currentOutboundMegolmSession->messageCount() + 1);
-        connection->saveCurrentOutboundMegolmSession(q, currentOutboundMegolmSession);
-        if(std::holds_alternative<QOlmError>(encrypted)) {
-            qWarning(E2EE) << "Error encrypting message" << std::get<QOlmError>(encrypted);
+        connection->saveCurrentOutboundMegolmSession(
+            id, *currentOutboundMegolmSession);
+        if(!encrypted) {
+            qWarning(E2EE) << "Error encrypting message" << encrypted.error();
             return {};
         }
-        auto encryptedEvent = new EncryptedEvent(std::get<QByteArray>(encrypted), q->connection()->olmAccount()->identityKeys().curve25519, q->connection()->deviceId(), currentOutboundMegolmSession->sessionId());
+        encryptedEvent = makeEvent<EncryptedEvent>(*encrypted, q->connection()->olmAccount()->identityKeys().curve25519, q->connection()->deviceId(), currentOutboundMegolmSession->sessionId());
         encryptedEvent->setTransactionId(connection->generateTxnId());
         encryptedEvent->setRoomId(id);
         encryptedEvent->setSender(connection->userId());
@@ -2103,7 +2050,7 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent)
             encryptedEvent->setRelation(pEvent->contentJson()["m.relates_to"_ls].toObject());
         }
         // We show the unencrypted event locally while pending. The echo check will throw the encrypted version out
-        _event = encryptedEvent;
+        _event = encryptedEvent.get();
 #endif
     }
 
@@ -2114,17 +2061,18 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent)
         Room::connect(call, &BaseJob::sentRequest, q, [this, txnId] {
             auto it = q->findPendingEvent(txnId);
             if (it == unsyncedEvents.end()) {
-                qCWarning(EVENTS) << "Pending event for transaction" << txnId
+                qWarning(EVENTS) << "Pending event for transaction" << txnId
                                  << "not found - got synced so soon?";
                 return;
             }
             it->setDeparted();
             emit q->pendingEventChanged(int(it - unsyncedEvents.begin()));
         });
-        Room::connect(call, &BaseJob::failure, q,
-                      std::bind(&Room::Private::onEventSendingFailure, this,
-                                txnId, call));
-        Room::connect(call, &BaseJob::success, q, [this, call, txnId, _event] {
+        Room::connect(call, &BaseJob::result, q, [this, txnId, call] {
+            if (!call->status().good()) {
+                onEventSendingFailure(txnId, call);
+                return;
+            }
             auto it = q->findPendingEvent(txnId);
             if (it != unsyncedEvents.end()) {
                 if (it->deliveryStatus() != EventStatus::ReachedServer) {
@@ -2132,13 +2080,10 @@ QString Room::Private::doSendEvent(const RoomEvent* pEvent)
                     emit q->pendingEventChanged(int(it - unsyncedEvents.begin()));
                 }
             } else
-                qCDebug(EVENTS) << "Pending event for transaction" << txnId
+                qDebug(EVENTS) << "Pending event for transaction" << txnId
                                << "already merged";
 
             emit q->messageSent(txnId, call->eventId());
-            if (q->usesEncryption()){
-                delete _event;
-            }
         });
     } else
         onEventSendingFailure(txnId);
@@ -2193,11 +2138,9 @@ QString Room::retryMessage(const QString& txnId)
     return d->doSendEvent(it->event());
 }
 
-// Lambda defers actual tr() invocation to the moment when translations are
-// initialised
-const auto FileTransferCancelledMsg = [] {
-    return Room::tr("File transfer cancelled");
-};
+// Using a function defers actual tr() invocation to the moment when
+// translations are initialised
+auto FileTransferCancelledMsg() { return Room::tr("File transfer cancelled"); }
 
 void Room::discardMessage(const QString& txnId)
 {
@@ -2262,28 +2205,26 @@ QString Room::Private::doPostFile(RoomEventPtr&& msgEvent, const QUrl& localUrl)
     // Below, the upload job is used as a context object to clean up connections
     const auto& transferJob = fileTransfers.value(txnId).job;
     connect(q, &Room::fileTransferCompleted, transferJob,
-            [this, txnId](const QString& tId, const QUrl&, const QUrl& mxcUri, Omittable<EncryptedFile> encryptedFile) {
-                if (tId != txnId)
-                    return;
+        [this, txnId](const QString& tId, const QUrl&,
+                      const FileSourceInfo& fileMetadata) {
+            if (tId != txnId)
+                return;
 
-                const auto it = q->findPendingEvent(txnId);
-                if (it != unsyncedEvents.end()) {
-                    it->setFileUploaded(mxcUri);
-                    if (encryptedFile) {
-                        it->setEncryptedFile(*encryptedFile);
-                    }
-                    emit q->pendingEventChanged(
-                        int(it - unsyncedEvents.begin()));
-                    doSendEvent(it->get());
-                } else {
-                    // Normally in this situation we should instruct
-                    // the media server to delete the file; alas, there's no
-                    // API specced for that.
-                    qCWarning(MAIN) << "File uploaded to" << mxcUri
-                                    << "but the event referring to it was "
-                                       "cancelled";
-                }
-            });
+            const auto it = q->findPendingEvent(txnId);
+            if (it != unsyncedEvents.end()) {
+                it->setFileUploaded(fileMetadata);
+                emit q->pendingEventChanged(int(it - unsyncedEvents.begin()));
+                doSendEvent(it->get());
+            } else {
+                // Normally in this situation we should instruct
+                // the media server to delete the file; alas, there's no
+                // API specced for that.
+                qCWarning(MAIN)
+                    << "File uploaded to" << getUrlFromSourceInfo(fileMetadata)
+                    << "but the event referring to it was "
+                       "cancelled";
+            }
+        });
     connect(q, &Room::fileTransferFailed, transferJob,
             [this, txnId](const QString& tId) {
                 if (tId != txnId)
@@ -2309,13 +2250,13 @@ QString Room::postFile(const QString& plainText,
     Q_ASSERT(content != nullptr && content->fileInfo() != nullptr);
     const auto* const fileInfo = content->fileInfo();
     Q_ASSERT(fileInfo != nullptr);
-    QFileInfo localFile { fileInfo->url.toLocalFile() };
+    QFileInfo localFile { fileInfo->url().toLocalFile() };
     Q_ASSERT(localFile.isFile());
 
     return d->doPostFile(
         makeEvent<RoomMessageEvent>(
             plainText, RoomMessageEvent::rawMsgTypeForFile(localFile), content),
-        fileInfo->url);
+        fileInfo->url());
 }
 
 #if QT_VERSION_MAJOR < 6
@@ -2343,8 +2284,7 @@ QString Room::postJson(const QString& matrixType,
 
 SetRoomStateWithKeyJob* Room::setState(const StateEventBase& evt)
 {
-    return d->requestSetState(evt.matrixType(), evt.stateKey(),
-                              evt.contentJson());
+    return setState(evt.matrixType(), evt.stateKey(), evt.contentJson());
 }
 
 SetRoomStateWithKeyJob* Room::setState(const QString& evtType,
@@ -2431,11 +2371,12 @@ void Room::sendCallCandidates(const QString& callId,
     d->sendEvent<CallCandidatesEvent>(callId, candidates);
 }
 
-void Room::answerCall(const QString& callId, const int lifetime,
+void Room::answerCall(const QString& callId, [[maybe_unused]] int lifetime,
                       const QString& sdp)
 {
-    Q_ASSERT(supportsCalls());
-    d->sendEvent<CallAnswerEvent>(callId, lifetime, sdp);
+    qCWarning(MAIN) << "To client developer: drop lifetime parameter from "
+                       "Room::answerCall(), it is no more accepted";
+    answerCall(callId, sdp);
 }
 
 void Room::answerCall(const QString& callId, const QString& sdp)
@@ -2450,15 +2391,18 @@ void Room::hangupCall(const QString& callId)
     d->sendEvent<CallHangupEvent>(callId);
 }
 
-void Room::getPreviousContent(int limit, const QString &filter) { d->getPreviousContent(limit, filter); }
+void Room::getPreviousContent(int limit, const QString& filter)
+{
+    d->getPreviousContent(limit, filter);
+}
 
 void Room::Private::getPreviousContent(int limit, const QString &filter)
 {
     if (isJobPending(eventsHistoryJob))
         return;
 
-    eventsHistoryJob =
-        connection->callApi<GetRoomEventsJob>(id, prevBatch, "b", "", limit, filter);
+    eventsHistoryJob = connection->callApi<GetRoomEventsJob>(id, "b", prevBatch,
+                                                             "", limit, filter);
     emit q->eventsHistoryJobChanged();
     connect(eventsHistoryJob, &BaseJob::success, q, [this] {
         prevBatch = eventsHistoryJob->end();
@@ -2506,18 +2450,18 @@ void Room::uploadFile(const QString& id, const QUrl& localFilename,
     Q_ASSERT_X(localFilename.isLocalFile(), __FUNCTION__,
                "localFilename should point at a local file");
     auto fileName = localFilename.toLocalFile();
-    Omittable<EncryptedFile> encryptedFile = std::nullopt;
+    FileSourceInfo fileMetadata;
 #ifdef Quotient_E2EE_ENABLED
     QTemporaryFile tempFile;
     if (usesEncryption()) {
         tempFile.open();
         QFile file(localFilename.toLocalFile());
         file.open(QFile::ReadOnly);
-        auto [e, data] = EncryptedFile::encryptFile(file.readAll());
+        QByteArray data;
+        std::tie(fileMetadata, data) = encryptFile(file.readAll());
         tempFile.write(data);
         tempFile.close();
         fileName = QFileInfo(tempFile).absoluteFilePath();
-        encryptedFile = e;
     }
 #endif
     auto job = connection()->uploadFile(fileName, overrideContentType);
@@ -2528,16 +2472,13 @@ void Room::uploadFile(const QString& id, const QUrl& localFilename,
                     d->fileTransfers[id].update(sent, total);
                     emit fileTransferProgress(id, sent, total);
                 });
-        connect(job, &BaseJob::success, this, [this, id, localFilename, job, encryptedFile] {
-            d->fileTransfers[id].status = FileTransferInfo::Completed;
-            if (encryptedFile) {
-                auto file = *encryptedFile;
-                file.url = QUrl(job->contentUri());
-                emit fileTransferCompleted(id, localFilename, QUrl(job->contentUri()), file);
-            } else {
-                emit fileTransferCompleted(id, localFilename, QUrl(job->contentUri()));
-            }
-        });
+        connect(job, &BaseJob::success, this,
+                [this, id, localFilename, job, fileMetadata]() mutable {
+                    // The lambda is mutable to change encryptedFileMetadata
+                    d->fileTransfers[id].status = FileTransferInfo::Completed;
+                    setUrlInSourceInfo(fileMetadata, QUrl(job->contentUri()));
+                    emit fileTransferCompleted(id, localFilename, fileMetadata);
+                });
         connect(job, &BaseJob::failure, this,
                 std::bind(&Private::failedTransfer, d, id, job->errorString()));
         emit newFileTransfer(id, localFilename);
@@ -2570,11 +2511,11 @@ void Room::downloadFile(const QString& eventId, const QUrl& localFilename)
                         << "has an empty or malformed mxc URL; won't download";
         return;
     }
-    const auto fileUrl = fileInfo->url;
+    const auto fileUrl = fileInfo->url();
     auto filePath = localFilename.toLocalFile();
     if (filePath.isEmpty()) { // Setup default file path
         filePath =
-            fileInfo->url.path().mid(1) % '_' % d->fileNameToDownload(event);
+            fileInfo->url().path().mid(1) % '_' % d->fileNameToDownload(event);
 
         if (filePath.size() > 200) // If too long, elide in the middle
             filePath.replace(128, filePath.size() - 192, "---");
@@ -2584,9 +2525,9 @@ void Room::downloadFile(const QString& eventId, const QUrl& localFilename)
     }
     DownloadFileJob *job = nullptr;
 #ifdef Quotient_E2EE_ENABLED
-    if(fileInfo->file.has_value()) {
-        auto file = *fileInfo->file;
-        job = connection()->downloadFile(fileUrl, file, filePath);
+    if (auto* fileMetadata =
+            std::get_if<EncryptedFileMetadata>(&fileInfo->source)) {
+        job = connection()->downloadFile(fileUrl, *fileMetadata, filePath);
     } else {
 #endif
     job = connection()->downloadFile(fileUrl, filePath);
@@ -2609,6 +2550,7 @@ void Room::downloadFile(const QString& eventId, const QUrl& localFilename)
         connect(job, &BaseJob::failure, this,
                 std::bind(&Private::failedTransfer, d, eventId,
                           job->errorString()));
+        emit newFileTransfer(eventId, localFilename);
     } else
         d->failedTransfer(eventId);
 }
@@ -2652,6 +2594,26 @@ void Room::Private::dropDuplicateEvents(RoomEvents& events) const
     events.erase(dupsBegin, events.end());
 }
 
+void Room::Private::decryptIncomingEvents(RoomEvents& events)
+{
+#ifdef Quotient_E2EE_ENABLED
+    QElapsedTimer et;
+    et.start();
+    size_t totalDecrypted = 0;
+    for (auto& eptr : events)
+        if (const auto& eeptr = eventCast<EncryptedEvent>(eptr)) {
+            if (auto decrypted = q->decryptMessage(*eeptr)) {
+                ++totalDecrypted;
+                auto&& oldEvent = exchange(eptr, move(decrypted));
+                eptr->setOriginalEvent(::move(oldEvent));
+            } else
+                undecryptedEvents[eeptr->sessionId()] += eeptr->id();
+        }
+    if (totalDecrypted > 5 || et.nsecsElapsed() >= profilerMinNsecs())
+        qDebug(PROFILER) << "Decrypted" << totalDecrypted << "events in" << et;
+#endif
+}
+
 /** Make a redacted event
  *
  * This applies the redaction procedure as defined by the CS API specification
@@ -2679,10 +2641,11 @@ RoomEventPtr makeRedacted(const RoomEvent& target,
           { QStringLiteral("ban"), QStringLiteral("events"),
             QStringLiteral("events_default"), QStringLiteral("kick"),
             QStringLiteral("redact"), QStringLiteral("state_default"),
-            QStringLiteral("users"), QStringLiteral("users_default") } }
-        //        , { RoomJoinRules::typeId(), { QStringLiteral("join_rule") } }
-        //        , { RoomHistoryVisibility::typeId(),
-        //                { QStringLiteral("history_visibility") } }
+            QStringLiteral("users"), QStringLiteral("users_default") } },
+        // TODO: Replace with RoomJoinRules::TypeId etc. once available
+        { "m.room.join_rules"_ls, { QStringLiteral("join_rule") } },
+        { "m.room.history_visibility"_ls,
+          { QStringLiteral("history_visibility") } }
     };
     for (auto it = originalJson.begin(); it != originalJson.end();) {
         if (!keepKeys.contains(it.key()))
@@ -2754,7 +2717,7 @@ bool Room::Private::processRedaction(const RedactionEvent& redaction)
     }
     if (const auto* reaction = eventCast<ReactionEvent>(oldEvent)) {
         const auto& targetEvtId = reaction->relation().eventId;
-        const QPair lookupKey { targetEvtId, EventRelation::AnnotationType };
+        const std::pair lookupKey { targetEvtId, EventRelation::AnnotationType };
         if (relations.contains(lookupKey)) {
             relations[lookupKey].removeOne(reaction);
             emit q->updatedEvent(targetEvtId);
@@ -2842,23 +2805,11 @@ Room::Changes Room::Private::addNewMessageEvents(RoomEvents&& events)
     if (events.empty())
         return Change::None;
 
+    decryptIncomingEvents(events);
+
     QElapsedTimer et;
     et.start();
 
-#ifdef Quotient_E2EE_ENABLED
-    for(long unsigned int i = 0; i < events.size(); i++) {
-        if(auto* encrypted = eventCast<EncryptedEvent>(events[i])) {
-            auto decrypted = q->decryptMessage(*encrypted);
-            if(decrypted) {
-                auto oldEvent = std::exchange(events[i], std::move(decrypted));
-                events[i]->setOriginalEvent(std::move(oldEvent));
-            } else {
-                undecryptedEvents[encrypted->sessionId()] += encrypted->id();
-            }
-        }
-    }
-#endif
-
     {
         // Pre-process redactions and edits so that events that get
         // redacted/replaced in the same batch landed in the timeline already
@@ -3002,30 +2953,17 @@ Room::Changes Room::Private::addNewMessageEvents(RoomEvents&& events)
 
 void Room::Private::addHistoricalMessageEvents(RoomEvents&& events)
 {
-    QElapsedTimer et;
-    et.start();
     const auto timelineSize = timeline.size();
 
     dropDuplicateEvents(events);
     if (events.empty())
         return;
 
-    Changes changes {};
-
-#ifdef Quotient_E2EE_ENABLED
-    for(long unsigned int i = 0; i < events.size(); i++) {
-        if(auto* encrypted = eventCast<EncryptedEvent>(events[i])) {
-            auto decrypted = q->decryptMessage(*encrypted);
-            if(decrypted) {
-                auto oldEvent = std::exchange(events[i], std::move(decrypted));
-                events[i]->setOriginalEvent(std::move(oldEvent));
-            } else {
-                undecryptedEvents[encrypted->sessionId()] += encrypted->id();
-            }
-        }
-    }
-#endif
+    decryptIncomingEvents(events);
 
+    QElapsedTimer et;
+    et.start();
+    Changes changes {};
     // In case of lazy-loading new members may be loaded with historical
     // messages. Also, the cache doesn't store events with empty content;
     // so when such events show up in the timeline they should be properly
@@ -3142,7 +3080,7 @@ Room::Changes Room::processStateEvent(const RoomEvent& e)
                 return false;
             }
             if (oldEncEvt
-                && oldEncEvt->encryption() != EncryptionEventContent::Undefined) {
+                && oldEncEvt->encryption() != EncryptionType::Undefined) {
                 qCWarning(STATE) << "The room is already encrypted but a new"
                                     " room encryption event arrived - ignoring";
                 return false;
@@ -3283,58 +3221,66 @@ Room::Changes Room::processEphemeralEvent(EventPtr&& event)
     Changes changes {};
     QElapsedTimer et;
     et.start();
-    if (auto* evt = eventCast<TypingEvent>(event)) {
-        d->usersTyping.clear();
-        d->usersTyping.reserve(evt->users().size()); // Assume all are members
-        for (const auto& userId : evt->users())
-            if (isMember(userId))
-                d->usersTyping.append(user(userId));
-
-        if (evt->users().size() > 3 || et.nsecsElapsed() >= profilerMinNsecs())
-            qCDebug(PROFILER)
-                << "Processing typing events from" << evt->users().size()
-                << "user(s) in" << objectName() << "took" << et;
-        emit typingChanged();
-    }
-    if (auto* evt = eventCast<ReceiptEvent>(event)) {
-        int totalReceipts = 0;
-        const auto& eventsWithReceipts = evt->eventsWithReceipts();
-        for (const auto& p : eventsWithReceipts) {
-            totalReceipts += p.receipts.size();
-            const auto newMarker = findInTimeline(p.evtId);
-            if (newMarker == historyEdge())
-                qCDebug(EPHEMERAL)
-                    << "Event" << p.evtId
-                    << "is not found; saving read receipt(s) anyway";
-            // If the event is not found (most likely, because it's too old and
-            // hasn't been fetched from the server yet) but there is a previous
-            // marker for a user, keep the previous marker because read receipts
-            // are not supposed to move backwards. Otherwise, blindly store
-            // the event id for this user and update the read marker when/if
-            // the event is fetched later on.
-            const auto updatedCount = std::count_if(
-                p.receipts.cbegin(), p.receipts.cend(),
-                [this, &changes, &newMarker, &evtId = p.evtId](const auto& r) {
-                    const auto change =
-                        d->setLastReadReceipt(r.userId, newMarker,
-                                              { evtId, r.timestamp });
-                    changes |= change;
-                    return change & Change::Any;
-                });
-
-            if (p.receipts.size() > 1)
-                qCDebug(EPHEMERAL) << p.evtId << "marked as read for"
-                                   << updatedCount << "user(s)";
-            if (updatedCount < p.receipts.size())
-                qCDebug(EPHEMERAL) << p.receipts.size() - updatedCount
-                                   << "receipts were skipped";
-        }
-        if (eventsWithReceipts.size() > 3 || totalReceipts > 10
-            || et.nsecsElapsed() >= profilerMinNsecs())
-            qCDebug(PROFILER) << "Processing" << totalReceipts
-                              << "receipt(s) on" << eventsWithReceipts.size()
-                              << "event(s) in" << objectName() << "took" << et;
-    }
+    switchOnType(*event,
+        [this, &et](const TypingEvent& evt) {
+            const auto& users = evt.users();
+            d->usersTyping.clear();
+            d->usersTyping.reserve(users.size()); // Assume all are members
+            for (const auto& userId : users)
+                if (isMember(userId))
+                    d->usersTyping.append(user(userId));
+
+            if (d->usersTyping.size() > 3
+                || et.nsecsElapsed() >= profilerMinNsecs())
+                qDebug(PROFILER)
+                    << "Processing typing events from" << users.size()
+                    << "user(s) in" << objectName() << "took" << et;
+            emit typingChanged();
+        },
+        [this, &changes, &et](const ReceiptEvent& evt) {
+            const auto& receiptsJson = evt.contentJson();
+            QVector<QString> updatedUserIds;
+            // Most often (especially for bigger batches), receipts are
+            // scattered across events (an anecdotal evidence showed 1.2-1.3
+            // receipts per event on average).
+            updatedUserIds.reserve(receiptsJson.size() * 2);
+            for (auto eventIt = receiptsJson.begin();
+                 eventIt != receiptsJson.end(); ++eventIt) {
+                const auto evtId = eventIt.key();
+                const auto newMarker = findInTimeline(evtId);
+                if (newMarker == historyEdge())
+                    qDebug(EPHEMERAL)
+                        << "Event" << evtId
+                        << "is not found; saving read receipt(s) anyway";
+                const auto reads =
+                    eventIt.value().toObject().value("m.read"_ls).toObject();
+                for (auto userIt = reads.begin(); userIt != reads.end();
+                     ++userIt) {
+                    ReadReceipt rr{ evtId,
+                                    fromJson<QDateTime>(
+                                        userIt->toObject().value("ts"_ls)) };
+                    const auto userId = userIt.key();
+                    if (userId == connection()->userId()) {
+                        // Local user is special, and will get a signal about
+                        // its read receipt separately from (and before) a
+                        // signal on everybody else. No particular reason, just
+                        // less cumbersome code.
+                        changes |= d->setLocalLastReadReceipt(newMarker, rr);
+                    } else if (d->setLastReadReceipt(userId, newMarker, rr)) {
+                        changes |= Change::Other;
+                        updatedUserIds.push_back(userId);
+                    }
+                }
+            }
+            if (updatedUserIds.size() > 10
+                || et.nsecsElapsed() >= profilerMinNsecs())
+                qDebug(PROFILER)
+                    << "Processing" << updatedUserIds.size()
+                    << "non-local receipt(s) on" << receiptsJson.size()
+                    << "event(s) in" << objectName() << "took" << et;
+            if (!updatedUserIds.empty())
+                emit lastReadEventChanged(updatedUserIds);
+        });
     return changes;
 }
 
@@ -3444,7 +3390,7 @@ QString Room::Private::calculateDisplayname() const
         shortlist = buildShortlist(membersLeft);
 
     QStringList names;
-    for (auto u : shortlist) {
+    for (const auto* u : shortlist) {
         if (u == nullptr || isLocalUser(u))
             break;
         // Only disambiguate if the room is not empty
@@ -3587,5 +3533,5 @@ void Room::activateEncryption()
         qCWarning(E2EE) << "Room" << objectName() << "is already encrypted";
         return;
     }
-    setState<EncryptionEvent>(EncryptionEventContent::MegolmV1AesSha2);
+    setState<EncryptionEvent>(EncryptionType::MegolmV1AesSha2);
 }
diff --git a/lib/room.h b/lib/room.h
index f5199eff..44504691 100644
--- a/lib/room.h
+++ b/lib/room.h
@@ -758,7 +758,8 @@ public:
     [[deprecated("Use currentState().get() instead; "
                  "make sure to check its result for nullptrs")]] //
     const Quotient::StateEventBase*
-    getCurrentState(const QString& evtType, const QString& stateKey = {}) const;
+    getCurrentState(const QString& evtType,
+                    const QString& stateKey = {}) const;
 
     /// Get a state event with the given event type and state key
     /*! This is a typesafe overload that accepts a C++ event type instead of
@@ -870,8 +871,9 @@ public Q_SLOTS:
     void inviteCall(const QString& callId, const int lifetime,
                     const QString& sdp);
     void sendCallCandidates(const QString& callId, const QJsonArray& candidates);
-    void answerCall(const QString& callId, const int lifetime,
-                    const QString& sdp);
+    //! \deprecated Lifetime argument is no more passed; use 2-arg
+    //!             Room::answerCall() instead
+    void answerCall(const QString& callId, int lifetime, const QString& sdp);
     void answerCall(const QString& callId, const QString& sdp);
     void hangupCall(const QString& callId);
 
@@ -971,9 +973,9 @@ Q_SIGNALS:
     void displayedChanged(bool displayed);
     void firstDisplayedEventChanged();
     void lastDisplayedEventChanged();
-    //! The event that m.read receipt points to has changed
+    //! The event the m.read receipt points to has changed for the listed users
     //! \sa lastReadReceipt
-    void lastReadEventChanged(Quotient::User* user);
+    void lastReadEventChanged(QVector<QString> userIds);
     void fullyReadMarkerMoved(QString fromEventId, QString toEventId);
     //! \deprecated since 0.7 - use fullyReadMarkerMoved
     void readMarkerMoved(QString fromEventId, QString toEventId);
@@ -997,7 +999,8 @@ Q_SIGNALS:
 
     void newFileTransfer(QString id, QUrl localFile);
     void fileTransferProgress(QString id, qint64 progress, qint64 total);
-    void fileTransferCompleted(QString id, QUrl localFile, QUrl mxcUrl, Omittable<EncryptedFile> encryptedFile = std::nullopt);
+    void fileTransferCompleted(QString id, QUrl localFile,
+                               FileSourceInfo fileMetadata);
     void fileTransferFailed(QString id, QString errorMessage = {});
     // fileTransferCancelled() is no more here; use fileTransferFailed() and
     // check the transfer status instead
diff --git a/lib/roomstateview.h b/lib/roomstateview.h
index cab69ae3..29cce00e 100644
--- a/lib/roomstateview.h
+++ b/lib/roomstateview.h
@@ -11,7 +11,8 @@ namespace Quotient {
 
 class Room;
 
-class RoomStateView : private QHash<StateEventKey, const StateEventBase*> {
+class QUOTIENT_API RoomStateView
+    : private QHash<StateEventKey, const StateEventBase*> {
     Q_GADGET
 public:
     const QHash<StateEventKey, const StateEventBase*>& events() const
diff --git a/lib/syncdata.cpp b/lib/syncdata.cpp
index 78957cbe..93416bc4 100644
--- a/lib/syncdata.cpp
+++ b/lib/syncdata.cpp
@@ -18,9 +18,10 @@ bool RoomSummary::isEmpty() const
 bool RoomSummary::merge(const RoomSummary& other)
 {
     // Using bitwise OR to prevent computation shortcut.
-    return joinedMemberCount.merge(other.joinedMemberCount)
-           | invitedMemberCount.merge(other.invitedMemberCount)
-           | heroes.merge(other.heroes);
+    return static_cast<bool>(
+        static_cast<int>(joinedMemberCount.merge(other.joinedMemberCount))
+        | static_cast<int>(invitedMemberCount.merge(other.invitedMemberCount))
+        | static_cast<int>(heroes.merge(other.heroes)));
 }
 
 QDebug Quotient::operator<<(QDebug dbg, const RoomSummary& rs)
@@ -142,7 +143,7 @@ SyncData::SyncData(const QString& cacheFileName)
                         << "is required; discarding the cache";
 }
 
-SyncDataList&& SyncData::takeRoomData() { return move(roomData); }
+SyncDataList SyncData::takeRoomData() { return move(roomData); }
 
 QString SyncData::fileNameForRoom(QString roomId)
 {
@@ -150,18 +151,18 @@ QString SyncData::fileNameForRoom(QString roomId)
     return roomId + ".json";
 }
 
-Events&& SyncData::takePresenceData() { return std::move(presenceData); }
+Events SyncData::takePresenceData() { return std::move(presenceData); }
 
-Events&& SyncData::takeAccountData() { return std::move(accountData); }
+Events SyncData::takeAccountData() { return std::move(accountData); }
 
-Events&& SyncData::takeToDeviceEvents() { return std::move(toDeviceEvents); }
+Events SyncData::takeToDeviceEvents() { return std::move(toDeviceEvents); }
 
 std::pair<int, int> SyncData::cacheVersion()
 {
     return { MajorCacheVersion, 2 };
 }
 
-DevicesList&& SyncData::takeDevicesList() { return std::move(devicesList); }
+DevicesList SyncData::takeDevicesList() { return std::move(devicesList); }
 
 QJsonObject SyncData::loadJson(const QString& fileName)
 {
@@ -179,12 +180,7 @@ QJsonObject SyncData::loadJson(const QString& fileName)
 
     const auto json = data.startsWith('{')
                           ? QJsonDocument::fromJson(data).object()
-#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
-                          : QCborValue::fromCbor(data).toJsonValue().toObject()
-#else
-                          : QJsonDocument::fromBinaryData(data).object()
-#endif
-        ;
+                          : QCborValue::fromCbor(data).toJsonValue().toObject();
     if (json.isEmpty()) {
         qCWarning(MAIN) << "State cache in" << fileName
                         << "is broken or empty, discarding";
diff --git a/lib/syncdata.h b/lib/syncdata.h
index 6b70140d..9358ec8f 100644
--- a/lib/syncdata.h
+++ b/lib/syncdata.h
@@ -98,15 +98,15 @@ public:
      */
     void parseJson(const QJsonObject& json, const QString& baseDir = {});
 
-    Events&& takePresenceData();
-    Events&& takeAccountData();
-    Events&& takeToDeviceEvents();
+    Events takePresenceData();
+    Events takeAccountData();
+    Events takeToDeviceEvents();
     const QHash<QString, int>& deviceOneTimeKeysCount() const
     {
         return deviceOneTimeKeysCount_;
     }
-    SyncDataList&& takeRoomData();
-    DevicesList&& takeDevicesList();
+    SyncDataList takeRoomData();
+    DevicesList takeDevicesList();
 
     QString nextBatch() const { return nextBatch_; }
 
diff --git a/lib/uri.cpp b/lib/uri.cpp
index 6b7d1d20..91751df0 100644
--- a/lib/uri.cpp
+++ b/lib/uri.cpp
@@ -171,7 +171,7 @@ QUrl Uri::toUrl(UriForm form) const
         return {};
 
     if (form == CanonicalUri || type() == NonMatrix)
-        return *this; // NOLINT(cppcoreguidelines-slicing): It's intentional
+        return SLICE(*this, QUrl);
 
     QUrl url;
     url.setScheme("https");
diff --git a/lib/util.cpp b/lib/util.cpp
index 03ebf325..359b2959 100644
--- a/lib/util.cpp
+++ b/lib/util.cpp
@@ -135,3 +135,12 @@ int Quotient::patchVersion()
 {
     return Quotient_VERSION_PATCH;
 }
+
+bool Quotient::encryptionSupported()
+{
+#ifdef Quotient_E2EE_ENABLED
+    return true;
+#else
+    return false;
+#endif
+}
diff --git a/lib/util.h b/lib/util.h
index 753eb1ea..46b1767e 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -37,6 +37,31 @@ static_assert(false, "Use Q_DISABLE_MOVE instead; Quotient enables it across all
         QT_WARNING_POP
 #endif
 
+#if __cpp_conditional_explicit >= 201806L
+#define QUO_IMPLICIT explicit(false)
+#else
+#define QUO_IMPLICIT
+#endif
+
+#define DECL_DEPRECATED_ENUMERATOR(Deprecated, Recommended) \
+    Deprecated Q_DECL_ENUMERATOR_DEPRECATED_X("Use " #Recommended) = Recommended
+
+/// \brief Copy an object with slicing
+///
+/// Unintended slicing is bad, which why there's a C++ Core Guideline that
+/// basically says "don't slice, or if you do, make it explicit". Sonar and
+/// clang-tidy have warnings matching this guideline; unfortunately, those
+/// warnings trigger even when you have a dedicated method (as the guideline
+/// recommends) that makes a slicing copy.
+///
+/// This macro is meant for cases when slicing is intended: the static cast
+/// silences the static analysis warning, and the macro appearance itself makes
+/// it very clear that slicing is wanted here. It is made as a macro
+/// (not as a function template) to support the case of private inheritance
+/// in which a function template would not be able to cast to the private base
+/// (see Uri::toUrl() for an example of just that situation).
+#define SLICE(Object, ToType) ToType{static_cast<const ToType&>(Object)}
+
 namespace Quotient {
 /// An equivalent of std::hash for QTypes to enable std::unordered_map<QType, ...>
 template <typename T>
@@ -93,8 +118,8 @@ private:
  */
 template <typename InputIt, typename ForwardIt, typename Pred>
 inline std::pair<InputIt, ForwardIt> findFirstOf(InputIt first, InputIt last,
-                                                    ForwardIt sFirst,
-                                                    ForwardIt sLast, Pred pred)
+                                                 ForwardIt sFirst,
+                                                 ForwardIt sLast, Pred pred)
 {
     for (; first != last; ++first)
         for (auto it = sFirst; it != sLast; ++it)
@@ -110,8 +135,8 @@ inline std::pair<InputIt, ForwardIt> findFirstOf(InputIt first, InputIt last,
 //! to define default constructors/operator=() out of line.
 //! Thanks to https://oliora.github.io/2015/12/29/pimpl-and-rule-of-zero.html
 //! for inspiration
-template <typename ImplType>
-using ImplPtr = std::unique_ptr<ImplType, void (*)(ImplType*)>;
+template <typename ImplType, typename TypeToDelete = ImplType>
+using ImplPtr = std::unique_ptr<ImplType, void (*)(TypeToDelete*)>;
 
 // Why this works (see also the link above): because this defers the moment
 // of requiring sizeof of ImplType to the place where makeImpl is invoked
@@ -131,20 +156,42 @@ using ImplPtr = std::unique_ptr<ImplType, void (*)(ImplType*)>;
 //!
 //! Since std::make_unique is not compatible with ImplPtr, this should be used
 //! in constructors of frontend classes to create implementation instances.
-template <typename ImplType, typename DeleterType = void (*)(ImplType*),
-          typename... ArgTs>
-inline ImplPtr<ImplType> makeImpl(ArgTs&&... args)
+template <typename ImplType, typename TypeToDelete = ImplType, typename... ArgTs>
+inline ImplPtr<ImplType, TypeToDelete> makeImpl(ArgTs&&... args)
+{
+    return ImplPtr<ImplType, TypeToDelete> {
+        new ImplType(std::forward<ArgTs>(args)...),
+        [](TypeToDelete* impl) { delete impl; }
+    };
+}
+
+template <typename ImplType, typename TypeToDelete = ImplType>
+inline ImplPtr<ImplType, TypeToDelete> acquireImpl(ImplType* from)
 {
-    return ImplPtr<ImplType> { new ImplType(std::forward<ArgTs>(args)...),
-                               [](ImplType* impl) { delete impl; } };
+    return ImplPtr<ImplType, TypeToDelete> { from, [](TypeToDelete* impl) {
+                                                delete impl;
+                                            } };
 }
 
-template <typename ImplType>
-const inline ImplPtr<ImplType> ZeroImpl()
+template <typename ImplType, typename TypeToDelete = ImplType>
+constexpr ImplPtr<ImplType, TypeToDelete> ZeroImpl()
 {
-    return { nullptr, [](ImplType*) { /* nullptr doesn't need deletion */ } };
+    return { nullptr, [](TypeToDelete*) { /* nullptr doesn't need deletion */ } };
 }
 
+//! \brief Multiplex several functors in one
+//!
+//! This is a well-known trick to wrap several lambdas into a single functor
+//! class that can be passed to std::visit.
+//! \sa  https://en.cppreference.com/w/cpp/utility/variant/visit
+template <typename... FunctorTs>
+struct Overloads : FunctorTs... {
+    using FunctorTs::operator()...;
+};
+
+template <typename... FunctorTs>
+Overloads(FunctorTs&&...) -> Overloads<FunctorTs...>;
+
 /** Convert what looks like a URL or a Matrix ID to an HTML hyperlink */
 QUOTIENT_API void linkifyUrls(QString& htmlEscapedText);
 
@@ -183,4 +230,5 @@ QUOTIENT_API QString versionString();
 QUOTIENT_API int majorVersion();
 QUOTIENT_API int minorVersion();
 QUOTIENT_API int patchVersion();
+QUOTIENT_API bool encryptionSupported();
 } // namespace Quotient
diff --git a/libquotient.pri b/libquotient.pri
index 677f60d3..1b4bd9c0 100644
--- a/libquotient.pri
+++ b/libquotient.pri
@@ -1,8 +1,7 @@
 QT += network multimedia
 QT -= gui
 
-# TODO: Having moved to Qt 5.12, replace c++1z with c++17 below
-CONFIG *= c++1z warn_on rtti_off create_prl object_parallel_to_source
+CONFIG *= c++20 warn_on rtti_off create_prl object_parallel_to_source
 
 win32-msvc* {
     # Quotient code base does not play well with NMake inference rules
diff --git a/quotest/quotest.cpp b/quotest/quotest.cpp
index 792faabd..90a5a69b 100644
--- a/quotest/quotest.cpp
+++ b/quotest/quotest.cpp
@@ -516,30 +516,14 @@ bool TestSuite::checkFileSendingOutcome(const TestToken& thisTest,
                         && e.hasFileContent()
                         && e.content()->fileInfo()->originalName == fileName
                         && testDownload(targetRoom->connection()->makeMediaUrl(
-                            e.content()->fileInfo()->url)));
+                            e.content()->fileInfo()->url())));
                 },
                 [this, thisTest](const RoomEvent&) { FAIL_TEST(); });
         });
     return true;
 }
 
-class CustomEvent : public RoomEvent {
-public:
-    DEFINE_EVENT_TYPEID("quotest.custom", CustomEvent)
-
-    CustomEvent(const QJsonObject& jo)
-        : RoomEvent(typeId(), jo)
-    {}
-    CustomEvent(int testValue)
-        : RoomEvent(typeId(),
-                    basicEventJson(matrixTypeId(),
-                                   QJsonObject { { "testValue"_ls,
-                                                   toJson(testValue) } }))
-    {}
-
-    auto testValue() const { return contentPart<int>("testValue"_ls); }
-};
-REGISTER_EVENT_TYPE(CustomEvent)
+DEFINE_SIMPLE_EVENT(CustomEvent, RoomEvent, "quotest.custom", int, testValue)
 
 TEST_IMPL(sendCustomEvent)
 {
@@ -604,6 +588,14 @@ TEST_IMPL(changeName)
                         if (!rme->newDisplayName()
                             || *rme->newDisplayName() != newName)
                             FAIL_TEST();
+                        // State events coming in the timeline are first
+                        // processed to change the room state and then as
+                        // timeline messages; aboutToAddNewMessages is triggered
+                        // when the state is already updated, so check that
+                        if (targetRoom->currentState().get<RoomMemberEvent>(
+                                localUser->id())
+                            != rme)
+                            FAIL_TEST();
                         clog << "Member rename successful, renaming the account"
                              << endl;
                         const auto newN = newName.mid(0, 5);
@@ -780,6 +772,14 @@ TEST_IMPL(visitResources)
                 clog << "Incorrect matrix.to representation:"
                      << matrixToUrl.toStdString() << endl;
             }
+            const auto checkResult = checkResource(connection(), uriString);
+            if ((checkResult != UriResolved && uri.type() != Uri::NonMatrix)
+                || (uri.type() == Uri::NonMatrix
+                    && checkResult != CouldNotResolve)) {
+                clog << "checkResource() returned incorrect result:"
+                     << checkResult;
+                FAIL_TEST();
+            }
             ud.visitResource(connection(), uriString);
             if (spy.count() != 1) {
                 clog << "Wrong number of signal emissions (" << spy.count()