Apple has stopped signing iOS 18.6.2, which means you cannot downgrade a device that has already been upgraded to iOS 26. The change was reported on September 22, 2025 and closes the window for reverting to iOS 18 after last week’s iOS 26 rollout.
Apple released iOS 26 on September 15, 2025. iOS 18.6.2 shipped earlier, on August 20, 2025. If you are still on iOS 18 and do not install iOS 26, you can remain where you are. If you upgraded, there is no official path back.
How it affects
Apple “signs” firmware to verify an install with its servers. When a build stops being signed, Apple’s verification servers reject restores and installs of that build. That makes downgrades to unsigned versions impossible through normal restore methods. In other words, the upgrade is one-way once Apple flips the switch.
Apple has applied the same unsigned status to related builds. The company is no longer signing iPadOS 18.6.2 and tvOS 18.6, so iPad and Apple TV users face the same restriction if they move to the new OS versions.
How to check and what you can do
If you want to confirm which builds Apple is signing for your device, check a signing-status tracker such as IPSW.dev or IPSW.me. Those sites query Apple’s servers and list the current signed versions per device. Back up your device before you install a major update. If you dislike iOS 26, your only safe option now is to restore to the latest build Apple still signs or wait for a future maintenance update that you prefer.
Apple is not forcing you to upgrade. You can keep using iOS 18 on devices you have not updated. The things here is this: upgrade deliberately. Once Apple stops signing a version, you lose the official downgrade route.
