Apple has stopped signing iOS 18.5. With this move, iPhone users are no longer able to revert to their previous software. This decision, taken following the recent release of iOS 18.6, means they can no longer upgrade to iOS 18.5.

The iOS 18.5 era has ended

Apple only allows the installation of software on iOS devices that has received verification from the company’s servers. In this system, each software version is signed for a specific period of time. However, shortly after releasing a new version, the company removes signature support for the previous version. This makes it technically impossible for users to revert to older software. Signature support for iOS 18.5 has also been discontinued accordingly.

iOS 18.6 was recently released by Apple for all compatible iPhone models. The version includes numerous fixes for system stability and security. In accordance with Apple’s update policies, this new version fixes more than 20 security vulnerabilities. The company believes that iOS 18.6 offers a more secure experience compared to the previous version.

Apple’s move mandates that users use the most current and secure software version available on their devices. Maintaining the latest software is critical, particularly for addressing security vulnerabilities and implementing new system improvements.

This development comes in the shadow of Apple’s planned fall release of iOS 26. iOS 26, unveiled at WWDC 25, is currently being tested in public beta. The final version is scheduled for September 2025, along with the launch of the iPhone 17 series.

Because iOS 18.5 has expired, downgrading to a version older than iOS 18.6 is currently not possible. This is a particularly important point for users who have installed beta software or are experiencing issues with their devices. These software-related decisions demonstrate Apple’s continued control of the ecosystem.