[Raize]

If you have a list of the phpBB modules you have installed you could probably talk to someone that is familiar with phpBB and they could determine whether or not they will affect the newer versions.

For the most part, the older versions of phpBB only need a few more slight tweaks to not be succeptible from the latest exploits. It's kind of dumb though, because the developers added some features that simply don't get used and those are what is exploitable.

A good way to determine if you're going to need to do any serious changes/reinstalls is to set up a beta site or beta forums, export the SQL with all the posts (minus the "General" and "Philosophy" forums since they are the largest, though the version of PHPBB you have might not let you export by forum, so you'd just have to manually remove the tables from the text file) and then load it into the beta forum. Assuming the images are hardlinked, you'd be okay, but even if they aren't, you don't need them to know whether or not the rest of the functionality is there.

Or you could just use IPB since it is generally more secure than PHPBB.