Possible to create ZIM file of whole Wiki? (my own, based on mediawiki)

I want to generate an offline ZIM version of our own Wiki (that runs on Mediawiki).The Collection extension is a breeze to install, but only works for selecting single pages, which in a next step can be combined into a single ZIM file.

But with a wiki of hundreds of pages this is too hard to do, based on single pages. I want to have a zim-dump of the whole wiki. I know it's possible, because there is also a zimfile for the complete wikipedia.

However, I can't find how this is done. Anyone able to help? Thanks in advance!