v1.152.0

Synapse 1.152.0 (2026-04-28)

No significant changes since 1.152.0rc1.

Configuration changes needed for deployments using workers

For deployments using workers, please note that this version introduces a new quarantined_media_changes stream writer, which may require configuration changes.
Please see the the relevant section in the upgrade notes for details.

Without configuring this new stream writer, only the main process will be able to handle the /media/quarantine admin API endpoints for quarantining media.

Synapse 1.152.0rc1 (2026-04-22)

Features

• Add a "Listing quarantined media changes" Admin API for retrieving a paginated record of when media became (un)quarantined. (#19558, #19677, #19694)
• Advertise MSC4445 sync timeline order in unstable_features. (#19642)
• Report the Rust compiler version used in the Prometheus metrics. Contributed by Noah Markert. (#19643)
• Passthrough 'article' and 'profile' OpenGraph metadata on URL preview requests. (#19659)
• Add a way to re-sign local events with a new signing key. (#19668)
• Support MSC4450: Identity Provider selection for User-Interactive Authentication with Legacy Single Sign-On. (#19693)
• Add experimental support for MSC4242: State DAGs. Excludes federation support. (#19424)
• Adds Admin API endpoints to
  list, fetch and delete user reports. (#19657)
• Reduce database disk space usage by pruning old rows from device_lists_changes_in_room. (#19473, #19709)

Bugfixes

• Reject device_keys: null in the request to POST /_matrix/client/v3/keys/upload, as per the spec. This was temporarily allowed as a workaround for misbehaving clients. (#19637)
• Fix database migrations failing on platforms where SQLite is configured with SQLITE_DBCONFIG_DEFENSIVE by default, such as macOS. (#19690)
• Fix a bug introduced in v1.145 where a non-admin could bypass admin checks for downloading remote quarantined media. This relied on the media already being previously present on the homeserver. (#19639)

Improved Documentation

• Include a workaround for running the unit tests with SQLite under recent versions of MacOS. (#19615)
• Fix Docker image link typo in worker docs. (#19645)
• Update the developer stream docs for creating a new stream to point out _setup_sequence(...) in portdb. (#19675)
• Update the developer stream docs for creating a new stream to highlight places that require documentation updates. (#19696)

Internal Changes

• Update CI to use re-usable Complement GitHub CI workflow. (#19533)
• Fix docstring for limit argument in _maybe_backfill_inner(...). (#19630)
• Document context for why increase timeout for policy server requests. (#19633)
• Run lint script to format Complement tests introduced in #19509. (#19636)
• Small simplifications to the events class. (#19680, #19712)
• Introduce spam_checker_spammy internal event metadata. (#19453)
• Add a FilteredEvent class that saves us copying events. (#19640)
• Convert EventInternalMetadata to use Arc<RwLock<_>>. (#19669)

v1.152.0rc1

Synapse 1.152.0rc1 (2026-04-22)

For deployments using workers, please note that this version introduces a new quarantined_media_changes stream writer, which may require configuration changes.
Please see the the relevant section in the upgrade notes for details.

Without configuring this new stream writer, only the main process will be able to handle the /media/quarantine admin API endpoints for quarantining media.

Features

• Add a "Listing quarantined media changes" Admin API for retrieving a paginated record of when media became (un)quarantined. (#19558, #19677)
• Advertise MSC4445 sync timeline order in unstable_features. (#19642)
• Report the Rust compiler version used in the Prometheus metrics. Contributed by Noah Markert. (#19643)
• Passthrough 'article' and 'profile' OpenGraph metadata on URL preview requests. (#19659)
• Add a way to re-sign local events with a new signing key. (#19668)
• Support MSC4450: Identity Provider selection for User-Interactive Authentication with Legacy Single Sign-On. (#19693)
• Add a "Listing quarantined media changes" Admin API for retrieving a paginated record of when media became (un)quarantined. (#19694)
• Add experimental support for MSC4242: State DAGs. Excludes federation support. (#19424)
• Adds Admin API endpoints to
  list, fetch and delete user reports. (#19657)
• Reduce database disk space usage by pruning old rows from device_lists_changes_in_room. (#19473, #19709)

Bugfixes

• Reject device_keys: null in the request to POST /_matrix/client/v3/keys/upload, as per the spec. This was temporarily allowed as a workaround for misbehaving clients. (#19637)
• Fix database migrations failing on platforms where SQLite is configured with SQLITE_DBCONFIG_DEFENSIVE by default, such as macOS. (#19690)
• Fix a bug introduced in v1.145 where a non-admin could bypass admin checks for downloading remote quarantined media. This relied on the media already being previously present on the homeserver. (#19639)

Improved Documentation

• Include a workaround for running the unit tests with SQLite under recent versions of MacOS. (#19615)
• Fix Docker image link typo in worker docs. (#19645)
• Update developer stream docs for creating a new stream to point out _setup_sequence(...) in portdb. (#19675)
• Update the developer stream docs for creating a new stream to highlight places that require documentation updates. (#19696)

Internal Changes

• Update CI to use re-usable Complement GitHub CI workflow. (#19533)
• Fix docstring for limit argument in _maybe_backfill_inner(...). (#19630)
• Document context for why increase timeout for policy server requests. (#19633)
• Run lint script to format Complement tests introduced in #19509. (#19636)
• Small simplifications to the events class. (#19680, #19712)
• Introduce spam_checker_spammy internal event metadata. (#19453)
• Add a FilteredEvent class that saves us copying events. (#19640)
• Convert EventInternalMetadata to use Arc<RwLock<_>>. (#19669)

v1.151.0

Synapse 1.151.0 (2026-04-07)

Bugfixes

• Fix KNOWN_ROOM_VERSIONS.__contains__ raising TypeError for non-string keys, which could cause /sync to fail for rooms with a NULL room version in the database. Bug introduced in #19589 as part of v1.151.0rc1. (#19649)

Synapse 1.151.0rc1 (2026-03-31)

Features

• Add stable support for MSC4284 Policy Servers. (#19503)
• Update and stabilize support for MSC2666: Get rooms in common with another user. Contributed by @tulir @ Beeper. (#19511)
• Updated experimental support for MSC4388: Secure out-of-band channel for sign in with QR. (#19573)
• Stabilize room_version and encryption fields in the space/room /hierarchy API (part of MSC3266). (#19576)
• Introduce a configuration option to allow using HTTP/2 over plaintext when Synapse connects to Matrix Authentication Service. (#19586)

Bugfixes

• Fix MSC4284 Policy Servers implementation to skip signing org.matrix.msc4284.policy and m.room.policy state events. (#19503)
• Correctly apply MSC4284 Policy Server signatures to events when the sender and policy server have the same server name. (#19503)
• Allow Synapse to start up even when discovery fails for an OpenID Connect provider. (#19509)
• Fix quarantine media admin APIs sometimes returning inaccurate counts for remote media. (#19559)
• Fix Build and push complement image CI job not having poetry available for the Complement runner script. (#19578)
• Increase timeout for policy server requests to avoid repeated requests for checking media. (#19629)

Deprecations and Removals

• Remove support for MSC3852: Expose user agent information on Device as the MSC was closed. (#19430)

Internal Changes

• Fix small comment typo in config output from the demo/start.sh script. (#19538)
• Add MSC3820 comment context to RoomVersion attributes. (#19577)
• Remove redacted_because from internal unsigned. (#19581)
• Prevent sending registration emails if registration is disabled. (#19585)
• Port RoomVersion to Rust. (#19589)
• Only show failing Complement tests in the formatted output in CI. (#19590)
• Ensure old Complement test files are removed when downloading a Complement checkout via ./scripts-dev/complement.sh. (#19592)
• Update HomeserverTestCase.pump() docstring to demystify behavior (Twisted reactor/clock). (#19602)
• Deprecate HomeserverTestCase.pump() in favor of more direct HomeserverTestCase.reactor.advance(...) usage. (#19602)
• Lower the Postgres database statement_timeout to 10m (previously 1h). (#19604)

v1.151.0rc1

Synapse 1.151.0rc1 (2026-03-31)

Features

• Add stable support for MSC4284 Policy Servers. (#19503)
• Update and stabilize support for MSC2666: Get rooms in common with another user. Contributed by @tulir @ Beeper. (#19511)
• Updated experimental support for MSC4388: Secure out-of-band channel for sign in with QR. (#19573)
• Stabilize room_version and encryption fields in the space/room /hierarchy API (part of MSC3266). (#19576)
• Introduce a configuration option to allow using HTTP/2 over plaintext when Synapse connects to Matrix Authentication Service. (#19586)

Bugfixes

• Fix MSC4284 Policy Servers implementation to skip signing org.matrix.msc4284.policy and m.room.policy state events. (#19503)
• Correctly apply MSC4284 Policy Server signatures to events when the sender and policy server have the same server name. (#19503)
• Allow Synapse to start up even when discovery fails for an OpenID Connect provider. (#19509)
• Fix quarantine media admin APIs sometimes returning inaccurate counts for remote media. (#19559)
• Fix Build and push complement image CI job not having poetry available for the Complement runner script. (#19578)
• Increase timeout for policy server requests to avoid repeated requests for checking media. (#19629)

Deprecations and Removals

• Remove support for MSC3852: Expose user agent information on Device as the MSC was closed. (#19430)

Internal Changes

• Fix small comment typo in config output from the demo/start.sh script. (#19538)
• Add MSC3820 comment context to RoomVersion attributes. (#19577)
• Remove redacted_because from internal unsigned. (#19581)
• Prevent sending registration emails if registration is disabled. (#19585)
• Port RoomVersion to Rust. (#19589)
• Only show failing Complement tests in the formatted output in CI. (#19590)
• Ensure old Complement test files are removed when downloading a Complement checkout via ./scripts-dev/complement.sh. (#19592)
• Update HomeserverTestCase.pump() docstring to demystify behavior (Twisted reactor/clock). (#19602)
• Deprecate HomeserverTestCase.pump() in favor of more direct HomeserverTestCase.reactor.advance(...) usage. (#19602)
• Lower the Postgres database statement_timeout to 10m (previously 1h). (#19604)

v1.150.0

Synapse 1.150.0 (2026-03-24)

No significant changes since 1.150.0rc1.

Upgrade notes

Please read the upgrade notes as this release includes a few changes that may affect your deployment.

Synapse 1.150.0rc1 (2026-03-17)

Features

• Add experimental support for the MSC4370 Federation API GET /extremities endpoint. (#19314)
• MSC4140: Cancellable delayed events: When persisting a delayed event to the timeline, include its delay_id in the event's unsigned section in /sync responses to the event sender. (#19479)
• Expose MSC4354 Sticky Events over the legacy (v3) /sync API. (#19487)
• When Matrix Authentication Service (MAS) integration is enabled, allow MAS to set the user locked status in Synapse. (#19554)

Bugfixes

• Fix Build and push complement image CI job pointing to non-existent image. (#19523)
• Fix a bug introduced in v1.26.0 that caused deactivated, erased users to not be removed from the user directory. (#19542)

Improved Documentation

• In the Admin API documentation, always express path parameters as /<param> instead of as /$param. (#19307)
• Update docs to clarify outbound_federation_restricted_to can also be used with the Secure Border Gateway (SBG). (#19517)
• Unify Complement developer docs. (#19518)

Internal Changes

• Put membership updates in a background resumable task when changing the avatar or the display name. (#19311)
• Add in-repo Complement test to sanity check Synapse version matches git checkout (testing what we think we are). (#19476)
• Migrate dev dependencies to PEP 735 dependency groups. (#19490)
• Remove the optional systemd-python dependency and the systemd extra on the synapse package. (#19491)
• Avoid re-computing the event ID when cloning events. (#19527)
• Allow caching of the /versions and /auth_metadata public endpoints. (#19530)
• Add a few labels to the number groupings in the Processed request logs. (#19548)

v1.150.0rc1

Synapse 1.150.0rc1 (2026-03-17)

Features

• Add experimental support for the MSC4370 Federation API GET /extremities endpoint. (#19314)
• MSC4140: Cancellable delayed events: When persisting a delayed event to the timeline, include its delay_id in the event's unsigned section in /sync responses to the event sender. (#19479)
• Expose MSC4354 Sticky Events over the legacy (v3) /sync API. (#19487)
• When Matrix Authentication Service (MAS) integration is enabled, allow MAS to set the user locked status in Synapse. (#19554)

Bugfixes

• Fix Build and push complement image CI job pointing to non-existent image. (#19523)
• Fix a bug introduced in v1.26.0 that caused deactivated, erased users to not be removed from the user directory. (#19542)

Improved Documentation

• In the Admin API documentation, always express path parameters as /<param> instead of as /$param. (#19307)
• Update docs to clarify outbound_federation_restricted_to can also be used with the Secure Border Gateway (SBG). (#19517)
• Unify Complement developer docs. (#19518)

Internal Changes

• Put membership updates in a background resumable task when changing the avatar or the display name. (#19311)
• Add in-repo Complement test to sanity check Synapse version matches git checkout (testing what we think we are). (#19476)
• Migrate dev dependencies to PEP 735 dependency groups. (#19490)
• Remove the optional systemd-python dependency and the systemd extra on the synapse package. (#19491)
• Avoid re-computing the event ID when cloning events. (#19527)
• Allow caching of the /versions and /auth_metadata public endpoints. (#19530)
• Add a few labels to the number groupings in the Processed request logs. (#19548)

v1.149.1

Synapse 1.149.1 (2026-03-11)

Internal Changes

• Bump matrix-synapse-ldap3 to 0.4.0 to support setuptools>=82.0.0. Fixes #19541. (#19543)

v1.149.0

Synapse 1.149.0 (2026-03-10)

No significant changes since 1.149.0rc1.

Synapse 1.149.0rc1 (2026-03-03)

Features

• Add experimental support for MSC4388: Secure out-of-band channel for sign in with QR. (#19127)
• Add stable support for MSC4380 invite blocking. (#19431)

Bugfixes

• Fix the 'Login as a user' Admin API not checking if the user exists before issuing an access token. (#18518)
• Fix /sync missing membership event in state_after (experimental MSC4222 implementation) in some scenarios. (#19460)

Internal Changes

• Add log to explain when and why we freeze objects in the garbage collector. (#19440)
• Better instrument JoinRoomAliasServlet with tracing. (#19461)
• Fix Complement CI not running against the code from our PRs. (#19475)
• Log docker system info in CI so we have a plain record of how GitHub runners evolve over time. (#19480)
• Rename the test_disconnect test helper so that pytest doesn't see it as a test. (#19486)
• Add a log line when we delete devices. Contributed by @bradtgmurray @ Beeper. (#19496)
• Pre-allocate the buffer based on the expected Content-Length with the Rust HTTP client. (#19498)
• Cancel long-running sync requests if the client has gone away. (#19499)
• Try and reduce reactor tick times when under heavy load. (#19507)
• Simplify Rust HTTP client response streaming and limiting. (#19510)
• Replace deprecated collection import locations with current locations. (#19515)
• Bump most locked Python dependencies to their latest versions. (#19519)

v1.149.0rc1

Synapse 1.149.0rc1 (2026-03-03)

Features

• Add experimental support for MSC4388: Secure out-of-band channel for sign in with QR. (#19127)
• Add stable support for MSC4380 invite blocking. (#19431)

Bugfixes

• Fix the 'Login as a user' Admin API not checking if the user exists before issuing an access token. (#18518)
• Fix /sync missing membership event in state_after (experimental MSC4222 implementation) in some scenarios. (#19460)

Internal Changes

• Add log to explain when and why we freeze objects in the garbage collector. (#19440)
• Better instrument JoinRoomAliasServlet with tracing. (#19461)
• Fix Complement CI not running against the code from our PRs. (#19475)
• Log docker system info in CI so we have a plain record of how GitHub runners evolve over time. (#19480)
• Rename the test_disconnect test helper so that pytest doesn't see it as a test. (#19486)
• Add a log line when we delete devices. Contributed by @bradtgmurray @ Beeper. (#19496)
• Pre-allocate the buffer based on the expected Content-Length with the Rust HTTP client. (#19498)
• Cancel long-running sync requests if the client has gone away. (#19499)
• Try and reduce reactor tick times when under heavy load. (#19507)
• Simplify Rust HTTP client response streaming and limiting. (#19510)
• Replace deprecated collection import locations with current locations. (#19515)
• Bump most locked Python dependencies to their latest versions. (#19519)

v1.148.0

Synapse 1.148.0 (2026-02-24)

No significant changes since 1.148.0rc1.

Synapse 1.148.0rc1 (2026-02-17)

Features

• Support sending and receiving MSC4354 Sticky Event metadata. (#19365)

Improved Documentation

• Fix reference to the experimental_features section of the configuration manual documentation. (#19435)

Deprecations and Removals

• Remove support for MSC3244: Room version capabilities as the MSC was rejected. (#19429)

Internal Changes

• Add in-repo Complement tests so we can test Synapse specific behavior at an end-to-end level. (#19406)
• Push Synapse docker images to Element OCI Registry. (#19420)
• Allow configuring the Rust HTTP client to use HTTP/2 only. (#19457)
• Correctly refuse to start if the Rust workspace config has changed and the Rust library has not been rebuilt. (#19470)