iPhone users running iOS 27 can no longer downgrade to iOS 26

Apple has recently stopped signing iOS 26.6.2, which prevents iPhone users from downgrading their operating system to iOS 26.6.2 if they are currently running iOS 27. This move was first noticed by Aaron Perris on X and highlights Apple's cautious approach when it comes to security. When a user attempts to install an iOS version on their device, the installation process involves checking with Apple's servers to ensure the version is still authorized for installation.

This process, known as signing, applies to both upgrading and downgrading to any iOS version. Apple maintains a relatively short list of signed iOS versions, which helps protect users from installing older versions that may contain security vulnerabilities that could be exploited by attackers. Although Apple released iOS 26.7 last week, the company has not yet officially provided a restore image for it, unlike iPadOS 26.7.

Currently, iPhone users who are still on an earlier version of iOS 26 can install iOS 26.7 over-the-air, but those already on iOS 27 cannot officially utilize it for downgrading.