BRP Central is now running on vBulletin 4 software and has been for some time. It's starting to show its age, as viewing it on a phone works pretty bad.
I have a license for the vBulletin 5 software, but it's still too bug-filled to be any use. It could be an option if the developers manage to iron it out though.
Invision Power Board is another option. I should be able to transfer posts from this forum to that pretty easy. I'm going to try it out for another forum first though, to get a feel for it before I consider it for BRP Central.
Other types of software may also turn up to be candidates.
An important question here is what kind of functionality you would like to see in the future? What are the most important aspects of this site's software to you?