I'm using 8.1 and it doesn't work for me on that natively either, nor at work with whatever older enterprise setup they are running at the office.
I was happy enough to get it working with the HTML editor option using my Chrome browser after I installed the
IE Tab extension for it. It's not elegant, but neither is the good old forum software so whetever works. It does seem to work well this way though.
A stern caution though. I spent a good half hour composing one the other night and somebody posted between when I started editing and when I clicked "post", and it hiccupped bad enough that my work was lost. When I know I want to spend some time on one, I'll do it in a text editor and paste it into the forum post editor box rather than take a chance for it to be erased. It probably saved you all from some really boring reading, but as for me I was bummed and gave up.
It would be nice if the forum software were more current but I guess that isn't ever easy, especially migrating all the old posts over to the new setup. Probably ain't free either.