Board Thread:General Discussion/@comment-31293812-20180603011324/@comment-1038387-20180603123322

A fork means it's split off, or branched out. The current MediaWiki is 1.30.0; Wikia forked at 1.19.24. While elements have been upgraded and new solutions added, a complete version update is impossible as there have been too many alterations. If they were to add Vector, they'd have to downgrade a lot of it to make it fit in their custom MediaWiki structure, or come up with new fixes.

I don't know the decision making about the IP tracking, but with a VPN, a user could bypass it and Wikia would still break the law. Or maybe they just want to offer the same product to everyone?

In the end, it's a business decision. Updating Monobook would be more trouble than it's (financially) worth.