Apple has stopped signing iOS 26.4, removing the option for iPhone users to downgrade from iOS 26.4.1 to the previous release. The change came shortly after iOS 26.4.1 rolled out, which is consistent with Apple’s usual update cycle where older builds are quickly phased out once a newer version becomes the default.
When Apple “stops signing” a version of iOS, it means that the software no longer passes Apple’s server-side verification process during installation. Even if the IPSW file is still available, the device cannot install it because Apple’s authentication system rejects the request. This is what makes downgrades impossible once signing ends.
This also affects restore workflows on macOS and Windows. Tools like Finder on Mac and the Apple Devices app on Windows rely on Apple’s signing window to reinstall older firmware. Once that window closes, restoring to iOS 26.4 is no longer supported through official methods.
Apple typically keeps older iOS versions signed for a short period after a new release. The reason is usually tied to stability and security. It reduces the chance of users staying on outdated builds that may contain bugs or unresolved vulnerabilities while also keeping the ecosystem aligned on the latest version.
iOS 26.4.1 is now the only publicly signed release. The update focused on bug fixes, including resolving an iCloud syncing issue that affected some users after updating to iOS 26.4. It also addressed behavior related to Stolen Device Protection on enterprise-managed devices. Apple did not publish specific CVE entries for this update, but it is currently the standard stable build for all compatible iPhones.
For users who delayed updating or hoped to roll back due to issues in iOS 26.4, that option is now closed. Devices updated to iOS 26.4.1 are effectively locked into Apple’s current signing path until the next update cycle begins. Apple is already testing iOS 26.5 in beta, which points to another incremental release in progress.
