The main thing to know about 1.3.0 is that is contains performance improvements to reduce disk I/O and reduce RAM usage. We’ve been running it on matrix.org for a week or so and are really pleased with the results.
Check out our message send heat map.
Other than that there are a bunch of bug fixes and tweaks to generally make things run more smoothly.
Fix 500 Internal Server Error on publicRooms when the public room list was
cached. (#5851)
Synapse 1.3.0rc1 (2019-08-13)
Features
Use M_USER_DEACTIVATED instead of M_UNKNOWN for errcode when a deactivated user attempts to login. (#5686)
Add sd_notify hooks to ease systemd integration and allows usage of Type=Notify. (#5732)
Synapse will no longer serve any media repo admin endpoints when enable_media_repo is set to False in the configuration. If a media repo worker is used, the admin APIs relating to the media repo will be served from it instead. (#5754, #5848)
Synapse can now be configured to not join remote rooms of a given "complexity" (currently, state events) over federation. This option can be used to prevent adverse performance on resource-constrained homeservers. (#5783)
Allow defining HTML templates to serve the user on account renewal attempt when using the account validity feature. (#5807)
Bugfixes
Fix UISIs during homeserver outage. (#5693, #5789)
Fix stack overflow in server key lookup code. (#5724)
start.sh no longer uses deprecated cli option. (#5725)
Log when we receive an event receipt from an unexpected origin. (#5743)
Fix debian packaging scripts to correctly build sid packages. (#5775)
Correctly handle redactions of redactions. (#5788)
Return 404 instead of 403 when accessing /rooms/{roomId}/event/{eventId} for an event without the appropriate permissions. (#5798)
Fix check that tombstone is a state event in push rules. (#5804)
Fix error when trying to login as a deactivated user when using a worker to handle login. (#5806)
Fix bug where user /sync stream could get wedged in rare circumstances. (#5825)
The purge_remote_media.sh script was fixed. (#5839)
Deprecations and Removals
Synapse now no longer accepts the -v/--verbose, -f/--log-file, or --log-config command line flags, and removes the deprecated verbose and log_file configuration file options. Users of these options should migrate their options into the dedicated log configuration. (#5678, #5729)