Jellyfin has released version 12.0, a major update that continues performance improvements started in version 10.11 and adds long-requested features for books and comics, according to the project’s official announcement.
The most visible change is the version numbering scheme itself. What would have been labeled 10.12.0 is now simply 12.0, marking the first time Jellyfin has dropped the leading “10” from its version number. According to the project, this change reflects feedback that previous numbering obscured the significance of major releases—10.11.0, which rebuilt the library database, appeared to be a minor update despite being a substantial release.
The upgrade includes significant database schema changes and requires users to stop Jellyfin, create a full manual backup of data and config directories, and run a complete library scan after upgrading. Users must be running Jellyfin 10.10.7 or any 10.11.x release before upgrading to 12.0. The first scan after upgrade will take longer than normal as Jellyfin checks every library item against files on disk and corrects previously misfiled content.
One major performance improvement involves how playlists and collections are stored. Previously, all items in a playlist were kept as a single list in the database, requiring the entire playlist to load for operations like getting item counts or editing. Now each item is stored as its own database row, allowing operations on large playlists without loading the entire structure. This same improvement applies to collections and boxsets.
Additional performance enhancements include faster Continue Watching, Next Up, rewatching, Latest Media for music, artist lookups, and watched count operations. Deleting large numbers of items no longer fails partway through, and heavy database maintenance no longer competes with library scans for resources.
The release adds episode alternate versions, extending a feature previously available only for movies. Users can now group episodes with broadcast and extended cuts, or different resolution copies, with resume data following the specific version being watched.
Books and comics receive native server support previously provided only through the Bookshelf plugin. The server now reads metadata directly from OPF and ComicInfo files without requiring plugins, generates posters for EPUBs and comic archives, extracts page counts from comic archives and PDFs, and extracts chapters from audiobooks. Metadata is also read from book and comic filenames when available.
The release includes security fixes and removes support for very old third-party clients. Legacy /emby/ and /mediabrowser/ API addresses have been removed, and the deprecated login method is now disabled. Third-party plugins built for 10.11 will not load on 12.0 and require updates from their authors.
Key facts
- Jellyfin drops the leading “10” from version numbering; 10.12.0 becomes 12.0
- Users must back up data and config before upgrading and run a full library scan post-upgrade
- Playlists and collections now store each item as a separate database row for improved performance
- Episode alternate versions now supported alongside existing movie alternate versions
- Books and comics receive native server support without requiring the Bookshelf plugin
- Very old third-party clients will stop working due to removed legacy API support