Apple stops signing iOS 10.2.1, 10.3 following iOS 10.3.1 release

Without signed code, iOS updates can't be installed. The tactic is a security and compatibility measure, but can create problems for people encountering newly-introduced bugs.

Released last month, iOS 10.3 switched devices to the more efficient Apple File System, and made some other additions such as a "Find My AirPods" feature and a reviews API.

iOS 10.3.1 was released on Apr. 3, and solved some problems with 10.3 including a Wi-Fi vulnerability. Apple also restored over-the-air updates for owners of the iPhone 5 and 5c, the last iPhones with 32-bit processors.

The next update, 10.3.2, is already in its second beta and appears to cut off support for 32-bit apps and hardware, meaning that 10.3.1 could be the last version of iOS for devices like the 5c.