Issues

• Add expiration/cleanup mechanism for e2e_room_keys

  A-DatabaseA-E2EEA-Performance
  element-hq/synapse#20361 · Filter by author watermelon0339 opened on Oct 15, 2026
  3

• Synapse prefers the most recent notary response for a key over the one with the highest validity

  A-FederationT-Defect
  element-hq/synapse#20358 · Filter by author ll-SKY-ll opened on Oct 14, 2026

• It might be possible for message retention policies to break sticky event catchup transactions by deleting the prev_event

  A-FederationA-RetentionA-Sticky-EventsT-DefectZ-Uncertain
  element-hq/synapse#20357 · Filter by author reivilibre opened on Oct 14, 2026
  

• [Sliding sync] to-device messages suddenly stop getting delivered on one device

  A-SyncA-to-device-messages
  element-hq/synapse#20355 · Filter by author uhoreg opened on Oct 13, 2026

• [Server Announcements] Handling read receipts

  A-Read-ReceiptsA-Server-Announcements
  element-hq/synapse#20351 · Filter by author anoadragon453 opened on Oct 13, 2026
  

• MSC4448: URL preview for site logos

  A-URL-PreviewT-ExperimentalFeature
  element-hq/synapse#20348 · Filter by author ZacksBot opened on Oct 13, 2026

• [Server Announcements] Injecting state events and messages into user's /sync streams

  A-Server-AnnouncementsA-Sync
  element-hq/synapse#20345 · Filter by author anoadragon453 opened on Oct 12, 2026
  

• [Server Announcements] Creating and configuring server announcement rooms

  A-ConfigA-Server-Announcements
  element-hq/synapse#20344 · Filter by author anoadragon453 opened on Oct 12, 2026
  5

  

• Appservice remains down with queued transactions until another room event is sent

  A-Application-Service
  element-hq/synapse#20342 · Filter by author rbondesson opened on Oct 12, 2026
  1

• Add support for Python 3.15

  A-Operabilitypython
  element-hq/synapse#20340 · Filter by author anoadragon453 opened on Oct 9, 2026

• CI run against Twisted trunk is failing

  element-hq/synapse#20329 · Filter by author github-actions opened on Oct 8, 2026

• Drop delayed_events_stream_pos table

  A-DatabaseT-TaskZ-Future-Maintenance
  element-hq/synapse#20311 · Filter by author AndrewFerr opened on Oct 5, 2026

• Allow hidden experimental config documentation

  A-ConfigA-DocsT-EnhancementT-ExperimentalFeature
  element-hq/synapse#20310 · Filter by author AndrewFerr opened on Oct 5, 2026
  1

• Stream positions end up ahead of Postgres sequences after a failover and fail-back (IncorrectDatabaseSetup, stuck sliding sync to-device)

  A-DatabaseA-Device-List-TrackingT-Defect
  element-hq/synapse#20305 · Filter by author perfectra1n opened on Oct 2, 2026
  2

• Our stream tables could store instance_id instead of instance_name to save on disk space and sharded token translation costs

  A-DatabaseA-Disk-Space
  element-hq/synapse#20304 · Filter by author reivilibre opened on Oct 2, 2026
  1

• Synapse pins transitive dependencies which can be eventually dropped by direct dependencies

  A-Packaging
  element-hq/synapse#20290 · Filter by author anoadragon453 opened on Sep 30, 2026
  5

• SerializationFailure retries exhausted when trying to reset Sliding Sync connection

  A-DatabaseA-SyncT-Defect
  element-hq/synapse#20284 · Filter by author MadLittleMods opened on Sep 28, 2026
  1

• Documented allow_underscore_prefixed_registration is never read; the code reads allow_underscore_prefixed_localpart

  A-ConfigA-Docs
  element-hq/synapse#20281 · Filter by author Santoshkumarpuppala opened on Sep 27, 2026
  1

• MSC4222 state_after loses membership changes when a lazy-loading client re-syncs from an older token

  A-Lazy-LoadingA-SyncT-Defect
  element-hq/synapse#20278 · Filter by author ara4n opened on Sep 26, 2026

• Sliding sync: sliding_sync_connection_required_state pruning races with a concurrent request, causing a ForeignKeyViolation (500)

  A-DatabaseA-Sync
  element-hq/synapse#20275 · Filter by author MadLittleMods opened on Sep 25, 2026
  1

• Simplified sliding sync (MSC4186) returns 500 instead of 400 when an appservice-masqueraded request has no device_id

  A-Application-ServiceA-Sync
  element-hq/synapse#20265 · Filter by author andrimuhyidin opened on Sep 24, 2026
  1

• Whitespace in room alias leads to error

  A-Room-Directory
  element-hq/synapse#20261 · Filter by author ClFeSc opened on Sep 23, 2026
  2

• [Epic] MSC4140: Cancellable Delayed Events

  A-Delayed-EventsZ-Epic
  element-hq/synapse#20254 · Filter by author barodeur opened on Sep 22, 2026

• Anticipated performance problems in message retention

  A-Message-Retention-PoliciesA-PerformanceA-RetentionZ-Uncertain
  element-hq/synapse#20248 · Filter by author reivilibre opened on Sep 21, 2026

• [Epic] Efficient Server Announcements

  A-Admin-APIA-Server-AnnouncementsT-Enhancement
  element-hq/synapse#20240 · Filter by author anoadragon453 opened on Sep 18, 2026
  4