“Apple detected that you are being targeted by a mercenary spyware attack that is trying to remotely compromise the iPhone associated with your Apple ID -xxx-,” it wrote in the warning to affected customers."
I would assume it's fake, part of some phishing scam. How can we know something like this is real? I'd be even more likely to think it's fake if it looks different than all the other messages I get.
Edited to add: As a comment below pointed out if you "sign in to appleid.apple.com" it'll confirm, which even I would trust! Thanks to quitit for pointing that out.
Edited to add: As a comment below pointed out if you "sign in to appleid.apple.com" it'll confirm, which even I would trust! Thanks to quitit for pointing that out.