The iOS 15.7.1 Release Candidate made available earlier this week appears to prevent Face ID from working on at least some iPhones, according to user reports across Reddit and Twitter. Affected devices include iPhone 12 Pro and iPhone 13 Pro models at a minimum, but it is quite possible that other models are impacted too.
Affected users who attempt to reset Face ID on their iPhone receive a "Face ID Is Not Available" error, resulting in facial recognition being completely broken. It is unclear what the cause of the issue is or whether Apple is aware of the problem. We have reached out to Apple for comment on the matter and will update this story if we hear back.
Release Candidates usually end up being identical to the final release for iOS updates, but it's possible that Apple could release a new Release Candidate with a fix ahead of iOS 15.7.1's expected release to the public next week.
Some users are not interested in updating to iOS 16, so it is important that Apple addresses this issue in iOS 15.7.1. There are also some devices that are compatible with iOS 15 but not iOS 16, including the iPhone 6s, iPhone 6s Plus, first-generation iPhone SE, seventh-generation iPod touch, iPhone 7, and iPhone 7 Plus.
(Thanks, @AppleSWUpdates!)
