Sorry for the late response. We had to put this project on hold for a while but resumed it now.
What I did so far was that I tried to use the demo package and exported it via the xwiki gui, then changed the hybernate to postgres and reimported this. That worked just fine, so we can exclude the jdbc driver and the login credentials as possible error cause.
After that, I dropped the xwiki database again and imported a dump of my old postgres 9.5 database into my postgres 11. Then I copied the old Data directory do a new location and changed the start.bat accordingly and got the following output log at my xwiki startup
2019_08_21.output.log (427.8 KB)
What am I missing? Maybe I did something wrong when I upgraded the database to 11, so if you could share best practice here, this would maybe already solve this issue.
Thanks in advance.