I have not as I wasn't thinking of backwards compatibility. This change is part of a rolling set of changes I intend to make to suit more recent technologies.
As for the claim that "nobody" has PHP 8.4 yet; SiteEU, WebWiz, HawkHost, Kinsta, SwitchWeb, NameCheap, GoDaddy, Google Cloud Hosting and AWS absolutely do support it. Honourable mention to cPanel's EasyApache which added PHP 8.4 support in December just gone.
Again, I will add backward compatibility for PHP 8.0. Might send up a couple of branched releases so people can select their desired version.