Shared library content lost

We are using JabRef to manage references in a shared library. The library is hosted on a PostgreSQL database which runs in a container on a NAS. Recently there was an update of privacy settings that were however unrelated to the container SQL database. Since then, connection to the database in the JabRef app can be established but all the content is lost. Are there any suggestions how the data can be recovered? Thanks a lot!

what version of JabRef are you using? Which update of privacy settings broke it? Could you provide details about the update?

If you are already using JabRef 5.8, there was a big change to the way JabRef saves its libraries. JabRef now automatically saves backups on the local system in the user data dir directory. So please check immediately, if some backups remain there. Until you have checked there, do NOT try to open and work with your library in any other way, because JabRef saves 10 backups at most and will overwrite old backups with newer ones, if you continue to try to work with that specific library.

The documentation about the backup manager is currently, unfortunately, out of date. I have not yet come around to document it properly. See here: Update info about backup manager and .sav and .bak files in docs · Issue #414 · JabRef/user-documentation · GitHub
There is still a little bit of ongoing work to improve upon it further and make it more convenient to use, so I was waiting for that process to end.

Maybe related (for 5.9 only)? Add Schema in PostgreSQL DB · Issue #9312 · JabRef/jabref · GitHub