To add to what has been said...
Do you have or can get server-level access to the current forum?
If yes, are you expecting to migrate forum history from the old platform to the new platform?
If yes, then it is really important to know what software and version is running the current forum so you can plan an orderly migration.
If no then your only concern is choice of forum software. Although it is not the most razzle-dazzle, social-media-look-alike platform in my mind it remains the best, most flexible, capable, and -- this is critical -- stable forum software platform. We have been using UBB since 2006 and it just works. Day after day, year after year. Yes there are features I would like added and sometimes the update schedule is frustrating but I have none of the daily operational complaints I hear from users of other forum software.
One of the nice things about UBB is how easy it is for non-coders to administer the forums. In addition there are some 3rd Party resources who know UBB inside out and can handle custom modifications and support at very reasonable rates.
If the current platform is already UBB then you need to plan a migration from the version in use to the most current version so that your site is clean and ready for the upcoming 7.6.0 version.
I recommend a hosted environment by a company familiar with php forum software sitting on top of a MySQL database. I found an EXCELLENT host in 2008 and have nothing but good things to say about them. Top notch in every way:
www.vertexthost.comAbbott
