We are working hard toward upgrading the Wikipedia ZIMs, but it is far from being an easy feat. I'm mostly solo on this, and far from dedicating 100% of my time to this, so it does not move very fast. We are quite close to being able to reach the goal however, probably only a matter of weeks now.

Bonus: the tool will now get pretty good at making a ZIM of any Mediawiki, not only Wikimedia ones, we expect for instance to work on all Fandom wikis somewhere this year since there is significant knowledge over there.

I haven't looked for documentation on creating my own zim file.