Regarding forum migration: there’s a flaw in Air3 that it doesn’t show the announcement banner put by the admins.
If you switch to Air the announcement is there.
Compare https://github.com/fluxbb/fluxbb/blob/b958c04d30a4d5d9e716f930c4c3846887c34f69/include/template/main.tpl
and https://github.com/natrius/air3/blob/master/Air3/main.tpl
There is no <pun_announcement> in Air3.
As Air3 is the default theme, almost nobody has seen this important message so far.