Apple has released two software updates to iOS 18.6. Since the iPhone software update has shipped without issue, and ...

People with devices running older iOS versions will need to update the operating system or find another way to back up their iPhones.

However, my positive experiences with the iOS 26 betas jibe with early impressions from several pros whose job includes testing new software on old devices.

Apple stops signing versions of iOS due to security issues being disclosed in older software versions and patched in newer software versions. Apple released iOS 18.6 on July 29.

Testing with developer and public beta versions went smoothly for even the oldest supported models. But there are safety measures if upgrading to the beta or release version goes awry.