It took an insanely long time (running overnight on a local VM), a little bit of money (with longer term savings), and some spit shine, but we are now on the new forum backend!
I think most things should work out of the box. Biggest thing that appears to be missing is any existing mentions, but we can live without that.
You should be able to login with your previous username and password. You can always do a password reset if that does not work.
Please comment here with questions or if anything isn’t working right.