I wish you a happy new year in a few hours! Get into 2020 well and don’t party tooooo hard.
Yesterday I finally upgraded my Debian servers from Stretch to Buster.
Buster does not contain Tomcat8 any more, so I thought it would be a good opportunity to also switch Xwiki from Tomcat 8 to 9.
Unfortunately, in https://www.xwiki.org/xwiki/bin/view/Documentation/AdminGuide/Installation/InstallationViaAPT/ there are not any upgrading instructions to do so, and simply installing
xwiki-tomcat9-mysql and adjusting the Tomcat server ports does not do the trick.
One thing I quickly figured out was that the data directory previously belonged to the tomcat8 user, but now has to be owned by the tomcat user (without any version indicator).
This still does not help, though, Xwiki spits out tons of Solr errors due to attachments which cannot be found and just presents a white page during login.
Before I post logs indicating that I missed the most basic adjustments, I’ll try it differently: Is switching from Tomcat8 to Tomcat9 a supported upgrade path (and if not, what should I do?) and if so, what are the basic requirements and upgrade steps I need to perform?