It's still using Xenforo - only we've went from version 1.5 (last release 8 years ago) to version 2.3.7 (latest release). So there's going to be a lot of changes. I announced the changes to moderators and admin and had 2 days of feedback, but I needed to move fast as I'm off work this week and won't have time to react during office hours next week. The upgrade needed to happen and is way too long overdue (because it was extremely difficult with all the customisations that were done with the previous version - and even just updating the data for 18 million posts took 8 hours...)