I haven't tested it on anything past 3.0.0, so I really don't know
I know it has some bugs that we've always just lived with.
Hehe. Tried it on 3.0.9, apart from the install guide fully needs updating as phpbb's code has changed,there were quite a few bugs which I didn't have time to check and note here, my database got FATAL ERROR: Undefined Method *profanity* in user (not by your mod) so i had to upload fresh install and fix the database. But just so you know it's incompatible. Cheers