I remember watching this project as it was getting started. It was a replacement to all those PHP forums, like PHPBB & Simple Machines BB. This claimed to have more modern features. It's also open-source, and you can self-host or pay them for hosting. (I recommend the latter)

And since we're on the subject, has Beehaw considered using an old PHP forum, like I mentioned earlier? They're really basic and quite nice, IMHO.