for the record, only the .io TLD will disappear (like .so, .nato, .yu, .dd, and more disappeared), itchio servers can still get a new domain name that is not a .io, and “reattach” their servers on it.
BUT, it would be way better to, instead of be in front of a fait accompli and rush things, plan ahead of time, and communicate while slowly migrate over a new domain.
for itchio team: it’s not you alone, game devs / studios also need time to update their websites links, api calls, and a lot more, and the sooner the better.