In the next couple hours I'll be starting the upgrade process to get us updated to SMF 2.0 RC5. Actual downtime should be pretty brief once the actual upgrade starts. If you post something about an hour from now don't expect it to be saved in a backup if the upgrade fails for some reason. Just forewarning.
That said, I don't expect there to be any issues as an upgrade done on a "test" version of this forum went through cleanly several weeks ago.