If it's not just a matter of the (ISO-8859-1?) text being read by the migration-converter in an encoding-dumb manner, but the 'new' forum home and/or backend manager itself refusing to announce anything but the lesser (UTF-8) character scheme, then it seems a bit backwards. Might be a misconfiguration of the freshly installed http-server (if that's part of what happened), or relying upon ride-sharing upon a 'new' host that's actually quite old
But I can't easily check the site's meta-info, from the device I'm currently on. Also, it could (if not just a matter of adding allowable encodings to go out) take a lot of effort to hunt down all kinds[1] of 'breakages', if the backend data itself has been denatured, and 'renature' them.
(Especially as it's a potentially lossy process, devoid of the meta info, so you can't disentangle a smart-quote that was converted to nonsense from a deliberate quoting of nonsense
to illustrate what that smartquote has become (or, maybe in some rare cases, actual legitimate funny sequences with an unescaped truth of their own). So it could make a lot of intentional "<a-acute><euro><whatever>" sequences appear as the thing that they
can mean, but not in this context.)
...erm, I'm not explaining things very well. I'm more sure that I know what I mean than I am that y'all do, when it comes down to it.
Anyway, for potential (future) testing of various possibilities, just leaving this here:
self redacted - hope that's not going to break anything!
pre-post edit: Ummm...Database Error
Please try again. If you come back to this error screen, report the error to an administrator.
Yes, it broke things on trying to post. Removing my test string.PPE2: In fact, it broke things so much that the Post button wouldn't work, nor did my on-screen keyboard (popped up if I tapped the Subject text-box, vanished if I tapped the message box here). Could select and copy the above(/below) and start a new reply to paste into. If you're reading this, that
worked...
[1]

- examples, that won't awkwardly further break or 'fix themselves' with no warning.