Overview
- Apple closed the signing window for iOS 26.4, which means iPhones on iOS 26.4.1 cannot be restored to the prior version.
- The iOS 26.4.1 update arrived last week with brief notes about bug fixes, and users report it restores broken iCloud syncing in some apps.
- Apple’s security pages list no CVE entries for iOS 26.4.1, so the precise reason for ending iOS 26.4 signing remains unclear.
- An Apple enterprise support note says Stolen Device Protection, which forces Face ID or Touch ID for sensitive actions, turns on automatically when moving from iOS 26.4 to iOS 26.4.1 on managed iPhones.
- Apple controls rollbacks by cryptographically signing each iOS build on its servers, so closing signing locks devices on the newest release and can frustrate jailbreakers or users trying to revert after issues.