Shame there's no blog post/article actually disclosing this change anywhere (how do we know this isn't a clone trying to steal market share or phish logins?)
The ifttt.ai page lists ifttt.com as canonical, guess that's a vaguely good sign (although it would have made it hard to submit to HN)
Seems like this must still be in progress, their home page redirects to the new .ai domain but there are still a lot of pages that load on their existing .com domain.