Features -------- - Add blacklist & whitelist of servers allowed to send events to a room via `m.room.server_acl` event. - Cache factor override system for specific caches ([\#3334](https://github.com/matrix-org/synapse/issues/3334)) - Add metrics to track appservice transactions ([\#3344](https://github.com/matrix-org/synapse/issues/3344)) - Try to log more helpful info when a sig verification fails ([\#3372](https://github.com/matrix-org/synapse/issues/3372)) - Synapse now uses the best performing JSON encoder/decoder according to your runtime (simplejson on CPython, stdlib json on PyPy). ([\#3462](https://github.com/matrix-org/synapse/issues/3462)) - Add optional ip\_range\_whitelist param to AS registration files to lock AS IP access ([\#3465](https://github.com/matrix-org/synapse/issues/3465)) - Reject invalid server names in federation requests ([\#3480](https://github.com/matrix-org/synapse/issues/3480)) - Reject invalid server names in homeserver.yaml ([\#3483](https://github.com/matrix-org/synapse/issues/3483)) Bugfixes -------- - Strip access\_token from outgoing requests ([\#3327](https://github.com/matrix-org/synapse/issues/3327)) - Redact AS tokens in logs ([\#3349](https://github.com/matrix-org/synapse/issues/3349)) - Fix federation backfill from SQLite servers ([\#3355](https://github.com/matrix-org/synapse/issues/3355)) - Fix event-purge-by-ts admin API ([\#3363](https://github.com/matrix-org/synapse/issues/3363)) - Fix event filtering in get\_missing\_events handler ([\#3371](https://github.com/matrix-org/synapse/issues/3371)) - Synapse is now stricter regarding accepting events which it cannot retrieve the prev\_events for. ([\#3456](https://github.com/matrix-org/synapse/issues/3456)) - Fix bug where synapse would explode when receiving unicode in HTTP User-Agent header ([\#3470](https://github.com/matrix-org/synapse/issues/3470)) - Invalidate cache on correct thread to avoid race ([\#3473](https://github.com/matrix-org/synapse/issues/3473)) Improved Documentation ---------------------- - `doc/postgres.rst`: fix display of the last command block. Thanks to \@ArchangeGabriel! ([\#3340](https://github.com/matrix-org/synapse/issues/3340)) Deprecations and Removals ------------------------- - Remove was\_forgotten\_at ([\#3324](https://github.com/matrix-org/synapse/issues/3324)) Misc ---- - [\#3332](https://github.com/matrix-org/synapse/issues/3332), [\#3341](https://github.com/matrix-org/synapse/issues/3341), [\#3347](https://github.com/matrix-org/synapse/issues/3347), [\#3348](https://github.com/matrix-org/synapse/issues/3348), [\#3356](https://github.com/matrix-org/synapse/issues/3356), [\#3385](https://github.com/matrix-org/synapse/issues/3385), [\#3446](https://github.com/matrix-org/synapse/issues/3446), [\#3447](https://github.com/matrix-org/synapse/issues/3447), [\#3467](https://github.com/matrix-org/synapse/issues/3467), [\#3474](https://github.com/matrix-org/synapse/issues/3474)