In theory, there should be a way to convert it. But it would take some know-how and knowledge of the inner-workings of phpBB to pull it off. They don't support this beta version.
OK, I did look back through the forum to see if this had been asked before, so apologies if I'm beating a dead horse here.
On a different forum I visit we just switched sites and forum software, (from ProBoard to SMF) and one of the admin wrote a script to move all the posts over (in the new forum they were all posted as the user 'archive). Of course everyone else had to re-register in the new forum. I'm guessing phpBB uses some kind of RDB? It sounds like it's more complicated than getting everything from one table and putting it into another somehow (I'm just throwing words around, I don't really know what I'm talking about here!).
So, I guess the question is, do we really want to update forum software? I do like this forum, but then again I like the new and shiny stuff too.
If we do want to update, here's a pretty crazy idea. If no one has the time to write or find a script...we could do it manually. In the time it would take me to find a script and understand if it would actually work, I probably could repost every thread (again using an 'archive' user). There currently are 2125 posts in this forum. I'm guessing I could update it manually in about two weeks. Anyone else who jumped in to the update project would cut down that time. But it would get done eventually. All the forum admin would need to do is install the new software on a new subdomain and set up an archive user.
Avatars, and probably other features as well, are disabled due to the roots of the forum. There was a big debate at the time, where newsgroup regulars were "concerned" (to put what nearly turned into an all-out brawl mildly) that any forum anybody would set up would by nature be bogged down with extras and graphics and slow loads and confusing features. So stuff like that was turned off.
I don't mind avatars, but it's been my experience that people are collectively unable to work withing community standards. There are tools in place to be sure avatars are a certain size (width/height, as well as file size), but I haven't checked to see how well it works. I've seen this abused elsewhere, even just in the content of the avatar itself.
I suppose if most people want it, it could be enabled. Most of the newsgroup regulars have pretty much steered clear of the forum, so maybe it's a non-issue. (After all, the IFDB got more sign-ups in its first week than this forum has gotten in its entire history -- for whatever reason, people avoid the forum.)
I know not all forums are the same, but in my limited experience hanging out on a dozen or so forums I haven't seen much of an issue, or heard of much of one, over avatars. I think people do like them, and it probably would help draw more people to the site if the forum looked like what they're used to. It might be my imagination but we seem to be getting a few new people here recently, and from looking around at the IF boards on other community game forums, I think the potential is there to draw more (non-R*IF) people to this site.