I tried various ways to upgrade but all of them ended in screens full of java error messages.
Xwiki is fine as long as it works, but an ovely complicated mess of dependencies
(application server, java, database server, search engine) with error logs spread all over the system as soon as something goes wrong.
I’m now giving up on Xwiki and will move the content to a different system… thank god I made a snapshot of the VM…