I'm preparing to upgrade the Rad Community Forums to YaBB 2.2, which was released November 8th (allowing time for them to correct any glitches discovered since the new release).
We currently use YaBB 2.1, which was released more than 2 years ago. So this should be a major upgrade.
I'm using the "safe" method of installing a new/clean copy of YaBB 2.2, leaving the current 2.1 forum up & running while I set-up the new 2.2 version (which takes a while).
After everything is hunky-dory (re-configured), I'll rename the currently-used directories to some other name, and rename the new 2.2 directories to those currently used by v2.1.
After editing one file (Paths.pl) to reflect these changes, we should be golden with a brand-spanking-new (upgraded) forum.
The forums contain more than 30,000 posts. People smarter than me frequent there. They deserve the new stuff.
I've already downloaded the new files and uploaded them to my server (physically located downtown Los Angeles), and chmod'ed everything (very tedious). Ready to "install" the new forum (by running "setup").
I also deleted many member-accounts (stayed up late last night). Anybody with 2 posts or less, and who hadn't visited the forums for 60 days was ax'ed. (They can always re-register.) You can glean more of the gory details » here. Upgrades suk. So many things can go wrong. Wish me luck.
For more along these lines, here's a Google search preconfigured for the query » upgrade community forum software yabb bulletin board message