Apple has closed the signing window for iOS 26. As a result, iPhone users who have updated their devices to iOS 27 are no longer able to roll back to the previous major operating system release.
Ceasing the signing of older software builds is standard operating procedure for Apple. The move helps ensure that users remain on the most up-to-date platform, ensuring access to the latest software enhancements and security fixes.
Once an iOS version is unsigned, official recovery tools will no longer validate installations of that build. Users currently running iOS 27 will need to remain on that software version or update to any newer releases made available in the future.
For more information and full details regarding this update, check the original report on 9to5Mac.
