The one issue I'm aware of as a result of doing this relates to email notifications, specifically to Microsoft email servers such as Hotmail, Outlook, Live etc.
Thanks to a useful feature at the people we rent the imaginary PC that is the server from, the IP address everyone uses to access here has stayed the same - it's why this change could be instant for everyone rather than having to wait for up to a day for everyone to see the new one, as happened with the other server change a couple of years ago.
But the notification emails are coming from a different IP address, the real one of the new server.
Possibly because the people who had the IP address before* were naughty, Microsoft email servers aren't accepting email from it. At all.
You can tell the level of competence involved by the way that the message saying that refers to clearing your IP address with a service that hasn't been called that for twelve years. And, in its new name, thinks we're ok.
Similarly, I've signed up with a Microsoft service to monitor how they see the IP address..
.. but because we send them so little email - about thirty a day at the moment - they don't show any data?!
It'll get sorted eventually, but this is why you've not getting any notifications if the board has an @hotmail, @outlook, @live etc email address recently. When it does get sorted, please read the emails - 'engagement' like this helps our rating with them.
TL;DR: Don't use Hotmail, Outlook or Live for your email address
Even perennial losers like Yahoo are doing better.
*
They've run out of new ones, so any you get are very likely to be second-hand. We'd use IPv6 which has more than enough to have one for every atom on Earth, but 22 years since its introduction, there are still ISPs that don't support it properly. Like mine.