Apple has stopped signing iOS 26.6.2, meaning iPhone users who have upgraded to iOS 27 can no longer downgrade their devices back to iOS 26.
The change closes the remaining route back to the previous major iOS release. Apple released iOS 26.6.2 on September 8, shortly before iOS 27 became available on September 14.
Apple routinely stops signing older versions of iOS after newer software is released. Once a version is no longer signed, Apple’s servers will reject attempts to restore an iPhone using that software.
The move means users experiencing problems after upgrading to iOS 27 will need to remain on iOS 27 and install subsequent updates as Apple releases fixes and improvements.
iOS 26.6.2 was a relatively small update that fixed an issue preventing some users from downloading a software update over a cellular data connection. Apple had previously released iOS 26.6 with bug fixes, security updates and Spotlight optimizations ahead of iOS 27.
Apple continues to develop iOS 27, with newer updates expected to address issues discovered following the major September release.