Synapse 1.157.0rc1 (2026-07-14)

Please check the relevant section in the upgrade notes as this release removes support for the deprecated MSC3861 Auth Delegation (experimental_features.msc3861).

Features

• MSC4140: Cancellable delayed events: Limit how many delayed events a user may have scheduled at once. (#19539)
• Support MSC4446 for moving fully read markers backwards. Contributed by @SpiritCroc @ Beeper. (#19663)
• Add before and after time filters to the 'Redact events of a user' Admin API. (#19802)
• Updated experimental support for MSC4388: Secure out-of-band channel for sign in with QR. (#19808)
• Add an exclude_rooms_from_presence configuration option to stop presence being routed between users solely because they share one of the listed rooms. (#19935)

Bugfixes

• MSC4140: Cancellable delayed events: Update error responses to match their format in the current draft of the MSC. (#19539)
• Lock Sliding Sync connections when inserting lazy members, to prevent repeated deadlocks. (#19826)
• Fix the flag_existing_quarantined_media background update skipping some quarantined remote media. Introduced in v1.152.0. (#19901)
• Fix a bug introduced in Synapse v1.150.0 where reactivating a deactivated and erased user did not restore their profile, breaking login, name changes, and invitations.
  Contributed by @m4us1ne. (#19902)
• Fix a regression where application services that opted into ephemeral events using the legacy de.sorunome.msc2409.push_ephemeral registration flag stopped receiving ephemeral events (including to-device messages used for encryption). Introduced in v1.156.0. (#19928)
• Fix a bug causing device list pruning to skip some rows when the transaction gets retried. (#19947)
• Fix presence states being shown to clients forever after presence is disabled, by marking any previously only users as offline. (#19948)
• Fix SYNAPSE_ASYNC_IO_REACTOR=1 on Python 3.14. (#19949)

Deprecations and Removals

• Remove support for experimental MSC3861 auth delegation, in favour of the stable Matrix Authentication Service integration support. See the upgrade notes. (#19895)

Internal Changes

• Port the synchronous core of client event serialization to Rust. (#19837, #19922)
• Update HomeserverTestCase.get_success(...) and friends to drive async Rust (Tokio runtime/thread pool). (#19871, #19879)
• Allow Rust code to have database access via Python database connection pool. (#19878)
• Add golangci-lint to CI. (#19888)
• Remove wall-clock dependency of test_redact_messages_all_rooms test, as this caused flakiness. (#19890)
• Change the MSC3814 dehydrated device /events endpoint from POST to GET. (#19896)
• Change the MSC3814 dehydrated device /events endpoint paging to match spec conventions. (#19897)
• Fix storage type mismatches where values were bound with a type that didn't match their database column. (#19911)
• Speed up deletion of old sliding sync connections by adding an index. (#19912)
• Add note to 3PID email token request unit tests that the endpoint being tested can have an expected, artificial delay of up to 1s. (#19916)
• Add an index to sliding_sync_connection_lazy_members to speed up deleting old sliding sync connection positions. (#19923)
• Fix test_lock_contention being flaky when running against PostgreSQL by budgeting CPU time rather than wall-clock time. (#19929)
• Fix Complement test flake when restarting Synapse workers (cross-test pollution caused by nginx upstreams being temporarily unavailable). (#19936)
• Add clean deploy FIXME note for TestOIDCProviderUnavailable (problem tracked by #19937). (#19938)
• Minor presence performance improvements for large servers. (#19939)
• Reduce replication traffic caused by presence. (#19941)
• Add last_active_granularity, sync_online_timeout and idle_timeout options to the presence config section to allow tuning the presence state machine timers. (#19942)