Board Thread:Support Requests - Designing Your Wiki/@comment-27179086-20200511080559/@comment-1038387-20200511124043

Rallyn4440 wrote: Can we please have an option to opt out of UCP. I’m trying to create the wiki before the anime ends in June and it’s impossible this way

Nope. Fandom is in a larger upgrade process and giving people the option to opt out now just creates more work down the line. It's perfectly possible to create the wiki and the contents, just some elements aren't fully working yet.

As for the navbox, that's code specific to their wiki. You can look for a simpler navbox template on the Templates wiki.