thanks for the tip… that itself was probably not the direct solution to my problem. But after I did a dump with the Windows Plex Server, I got different error messages in the DB Browser. This made me update the browser and finally this link https://forums.plex.tv/t/can-no-longer-update-library-database-with-sqlite3/701405/43 helped me!!! … 
the only problem i have now is that the old viewstats are no longer recognized. Is it possible that something has changed here too?
