Bottom Line: Do Not Install the Downloaded Debian Package Inside the Plex Container
The Plex notification offers a server update, but a ZimaOS Plex app is containerized. Updating the container by SSH with Debian package instructions can create an unsupported mixed state. Update through the container image/version settings instead.
For the LinuxServer Plex Image, VERSION Has Specific Meanings
The old thread changed VERSION from docker to latest, saved, and the update worked. Current LinuxServer documentation still defines the values: docker lets the container image determine the public Plex version; latest updates to the newest Plex build your account is entitled to; public keeps Plex Pass users on public builds.
See the LinuxServer Plex documentation and the upstream container repository.
Back Up /config Before Changing Update Behavior
Your media files are not your Plex database. Preserve the persistent /config mapping, which contains the library database, metadata and server preferences. If that mapping is correct, recreating the container should not erase the Plex library state.
The Plex hardware requirements guide explains why the config path and media mounts should stay persistent.
Prefer an Image Pull and Container Recreation Over In-Container Package Updates
LinuxServer's current update guidance is to pull the image and recreate the container. In ZimaOS, use the app update/save/restart path that performs the equivalent image refresh rather than running apt inside the Plex container.
If Plex Still Says an Update Is Available
Check the running Plex server version, the container image version and your VERSION setting separately. A Plex Pass account may be entitled to a build that differs from the latest public Docker image.
For the broader current app model, see the ZimaOS App Store hardware and app guide.
