Apple has officially closed the signing window for iOS 26.4.2 and iPadOS 26.4.2, which means users who have already moved to iOS 26.5 can no longer roll back to the older release.
That change follows Apple’s usual update pattern. After a newer version ships, the company often keeps the previous build signed for a short period so users can downgrade if they run into major bugs or compatibility issues. Once that observation window ends, Apple stops verifying the older firmware and the downgrade path disappears.
The reason this matters is tied to Apple’s firmware verification system. Before an iPhone or iPad can install any version of iOS or iPadOS, Apple’s servers must still be authorizing that build. When the company closes the Apple signing window, devices can no longer install that unsigned version through the normal restore or downgrade process.
So in practical terms, anyone who updated to iOS 26.5 is now locked out of returning to 26.4.2. For people who were waiting to see whether the newer release caused issues, that decision window is now over.
Apple typically makes this move after it is satisfied that no widespread problems require keeping the earlier version available for fallback. It’s a routine step, but it still matters to users who prefer holding onto an older build for stability, jailbreak-related reasons, or app compatibility checks.
For most users, the update path stays straightforward: once Apple closes signing on the old version, the current public release becomes the only standard supported option.
