We’re excited to announce the fourth release candidate for Jellyfin 12.0! This preview build is meant for early testers who want to help us iron out any remaining bugs ahead of the final release. As always, make sure you stop your server and take a full backup before upgrading.
A note about versioning
Starting with this release, we’re officially dropping the old ’10.’ prefix. That means 10.11.x now becomes 12.x. The reasoning is straightforward: at this stage of the project, we don’t foresee the hard API break we once planned for, and the previous numbering was confusing many users about what a ‘major’ release actually meant. If you’d like more context, check out the RC1 release notes.
What’s new?
Performance is the name of the game this time around. The 10.11.0 release brought a massive backend rewrite that worked overall but had plenty of rough edges. This release polishes those edges, giving all users a snappier, more stable experience. You’ll also find a host of smaller fixes, improvements, and updated translations. For a complete list of changes, you can browse our draft release notes or the web-side changelog.
Important: You must be on Jellyfin 10.10.7 or newer (ideally 10.11.11) before upgrading; otherwise, the upgrade will fail. Upgrade to one of those versions first!
Note: When Jellyfin 12.x starts for the first time, it will run several database migrations, which can take a few minutes. Please be patient and don’t interrupt the process. You can monitor the detailed progress on your local network via the newly improved startup UI, or see general progress off-network by visiting the server URL in your browser during startup.
Note: If you install this release candidate, be sure to disable all external plugins and reinstall them from the unstable plugin repository. Otherwise, plugins may not load correctly and could cause unexpected issues.
Installing
This preview is available in all our usual formats, though not via the Apt repository or the latest Docker tag.
- For non‑Docker setups, grab the files manually from our repository by selecting ‘Stable Preview’ for your operating system.
- If you use Docker, simply pull the
12.0-rc4orpreviewtag.
What’s changed since RC3
This update brings a mix of performance refinements, bug fixes, and a few new integration touches. On the database side, queries have been streamlined to reduce overhead—notably by cutting correlated subqueries and cleaning up how sorting works. Playback and metadata handling also got attention: MP4 files now display audio and subtitle tracks correctly, 3D format detection works even when the tag sits at the end of a file path, and extras are named and versioned properly again. Trailer years and SyncPlay queue indices are no longer off, and episode titles with hyphenated numbers won’t be mistakenly parsed as multi‑episode ranges.
For media providers, we’ve added TheAudioDB artist search, a TMDB missing episode provider, and fixed several issues with series merging and missing collection folder posters after initial scans. Live TV users will appreciate that streaming URLs are no longer unreachable from the client side, and a fix for Windows ensures storage info is looked up correctly. Under the hood, encoder validation should be smoother, and a small tweak allows graphical subtitles to be rendered by the client even during remuxing. Overall, the release is designed to make day‑to‑day use faster and more reliable.
We also want to welcome new contributors: rwebster85, paoloantinori, elio42, and alchemyyy—their first contributions are part of this RC. For the full technical diff, see the complete changelog.
