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v1.153.0 Feature

This release adds 3 notable features for engineering teams evaluating rollout.

Published 15d Communication & Email
✓ No known CVEs patched
Read the diff → Tool health → What is this tool? →

✓ No known CVEs patched in this version

Affected surfaces

rbac

Summary

AI summary

Broad release touches Bugfixes, Internal Changes, Synapse 1.153.0rc1, and https://github.com/element-hq/synapse/issues/19714.

Changes in this release

Feature Medium

Make ACLs apply to EDUs per MSC4163.

Make ACLs apply to EDUs per MSC4163.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: high

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Feature Medium

Implement partial MSC4311: `m.room.create` required in stripped invite_state/knock_state.

Implement partial MSC4311: `m.room.create` required in stripped invite_state/knock_state.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: high

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Feature Medium

Have Simplified Sliding Sync return new response immediately on room subscription change.

Have Simplified Sliding Sync return new response immediately on room subscription change.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: high

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Feature Medium

Expose tombstoned and replacement_room in admin API room details endpoint.

Expose tombstoned and replacement_room in admin API room details endpoint.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

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Dependency Medium

Configure Dependabot to update Python dependencies only in lockfile unless widening upper bounds.

Configure Dependabot to update Python dependencies only in lockfile unless widening upper bounds.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Performance Medium

Add a Rust canonical JSON serializer.

Add a Rust canonical JSON serializer.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Performance Medium

Reduce WORKER_LOCK_MAX_RETRY_INTERVAL to 5 seconds to reduce idle time after lock release.

Reduce WORKER_LOCK_MAX_RETRY_INTERVAL to 5 seconds to reduce idle time after lock release.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

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Deprecation Medium

Remove experimental config flag msc3266_enabled, stabilizing Room summary API.

Remove experimental config flag msc3266_enabled, stabilizing Room summary API.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Bugfix Medium

Allow self-requested user erasure upon account deactivation even if profile changes disabled.

Allow self-requested user erasure upon account deactivation even if profile changes disabled.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: high

 —
Bugfix Medium

Fix Fedora/EPEL packaging issue caused by unnecessary authlib version bump in pyproject.toml.

Fix Fedora/EPEL packaging issue caused by unnecessary authlib version bump in pyproject.toml.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: high

 —
Bugfix Medium

Fix Synapse not backfilling new history with pagination tokens near backward extremity.

Fix Synapse not backfilling new history with pagination tokens near backward extremity.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Bugfix Medium

Fix mutation of power level event when upgrading a room to version 12.

Fix mutation of power level event when upgrading a room to version 12.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Bugfix Medium

Revert Simplified Sliding Sync change due to performance problems.

Revert Simplified Sliding Sync change due to performance problems.

Source: granite4.1:30b@2026-05-19-audit

Confidence: low

 —
Refactor Medium

Port Event.signatures field to Rust.

Port Event.signatures field to Rust.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Refactor Medium

Port Event.unsigned field to Rust.

Port Event.unsigned field to Rust.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Refactor Medium

Force keyword-only arguments for Duration so time units must be specified.

Force keyword-only arguments for Duration so time units must be specified.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Other Medium

Add warning about known problems when configuring use_frozen_dicts.

Add warning about known problems when configuring use_frozen_dicts.

Source: granite4.1:8b-q6_K@2026-05-19

Confidence: low

 —
Full changelog

Synapse 1.153.0 (2026-05-19)

No significant changes since 1.153.0rc3.

Synapse 1.153.0rc3 (2026-05-15)

Bugfixes

  • Revert 'Have MSC4186: Simplified Sliding Sync return a new response immediately if a room subscription has changed and produced a new response. (#19714)' (introduced in 1.153.0rc1) due to performance problems. (#19784)

Synapse 1.153.0rc2 (2026-05-13)

Bugfixes

  • Correctly handle arbitrary precision integers in unsigned field of events. The bug was introduced in 1.153.0rc1. (#19769)

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)

Bugfixes

  • 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)

Improved Documentation

  • Add warning about known problems when configuring use_frozen_dicts. (#19711)

Internal Changes

  • 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)
View diff on GitHub

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About synapse

Synapse: Matrix homeserver written in Python/Twisted + Rust

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