Synapse 1.153.0rc1 (2026-05-08)

Features

Make ACLs apply to EDUs per MSC4163. (#18475)
Stabilize MSC3266: Room summary API, removing the experimental config flag msc3266_enabled. Contributed by @dasha-uwu. (#19720)
Partial MSC4311 implementation: m.room.create is now a required part of stripped invite_state/knock_state . Contributed by @FrenchGithubUser @famedly. (#19722)
Expose tombstoned and replacement_room in room details on admin API endpoint GET /_synapse/admin/v1/rooms/<room_id>. Contributed by Noah Markert. (#19737)

Allow self-requested user erasure (upon account deactivation) to succeed even if Synapse has disabled profile changes. Contributed by Famedly. (#19398)
Fix Synapse not backfilling new history when attempting to use a pagination token near a backward extremity. (#19611)
Have MSC4186: Simplified Sliding Sync return a new response immediately if a room subscription has changed and produced a new response. (#19714)
Fix a bug where when upgrading a room to room version 12, the power level event in the old room got temporarily mutated to remove the user upgrading the room's power. (#19727)
Fix packaging for Fedora and EPEL caused by unnecessary bumping authlib minimum version requirement in pyproject.toml file. Contributed by Oleg Girko. (#19742)

Port Event.signatures field to Rust. (#19706)
Port Event.unsigned field to Rust. (#19708)
Add a Rust canonical JSON serializer. (#19739, #19763)
Configure Dependabot to only update Python dependencies in the lockfile, unless widening upper bounds. (#19743)
Reduce WORKER_LOCK_MAX_RETRY_INTERVAL to 5 seconds to reduce idle time after lock is released. (#19755)
Force keyword-only arguments for Duration so time units have to be specified. (#19756)