Documentation on the wiki has always been a bit of a hit'n'miss affair.
Members of the team are spread thin at the moment and keeping the documentation up-to-date, though important, often gets left out. Sorry for that.
The in-game documentation would probably be your best bet or as is suggested here look through the GitHub repo, though that too is getting left behind, at least writing up the changelog is, not the actual progress on the code.
There's nothing too extraordinary that you will need to watch out for, Leaders, techs, units, buildings, Wonders, policies and beliefs all have something changed about them. Some big changes, some minor.
