Is is related. After the up maintenance, which included migrating to a new server and upgrading the forum software, the forums would freeze and stop responding. Depending on your browser you might get an error message or you might just get a blank white page.
The hosting company was completely useless, but I found a possible solution on the software company's web site. The suggestion was to delete temporary files generated by the software. Every page in the forum is built from queries to a database. These queries take time. SO, to save time and make things more efficient, the forum software has a feature where it saves the results from a query so that the next time someone wants to load the same page, it doesn't have to do the database query, it can just use the previous results. Well, for some unknown reason at some random time, one of those stashed files would get messed up and things would get confused and lock up. The solution was to simply delete all those stashed results to get rid of the bad one.
This worked great. I deleted all those temporary saved results and the forum worked great. Except, of course, with all those files gone, it would start saving the results from new queries and at some point, another one of those new temporary files would go bad and things would lock up again. And I wouldn't know things had locked up again until I checked the forums. Sometimes I would delete the files and things were good for weeks, sometimes days, sometimes only hours. The forums would be down, I could fix the problem, the forums would be working for a few hours, then be broken again. I got to the point where I set things up to automatically delete all those temporary files every night at 3am. But sometimes I'd check the forums the next day at things were still down. My final solution was to just simply disable the whole "saving results" efficiency thing. In theory, the response time is a tiny bit slower, but the forum has been up consistently.
Now, there are still some annoying issues like the old gallery no longer being supported, the post counts not updating like they should, and that when you create a new topic it will forget to reload the page and time out . . .