If you're starting a NEW forum, UTF8.
If you have the TIME to CONVERT your forum (if you use non-latin characters, you'll likely need to spend some $), UTF8
If you have an EXISTING forum, DO NOT want to convert, or if your native forum language is NOT English, then you'd probably just want to stay at iso-8859-1.
also, well done on new version 7.6 @id / giz !!
Danka, it was a long road, lol.