After a few hours of availability, Apple pulled the over-the-air iOS 10.3 update for the iPhone 5 and 5c, though the legacy devices can still be updated through iTunes on a Mac or PC.
Why the move was made is not yet clear. There is seemingly no swell of users complaining about failings of the update on social media, nor any indication of a large amount of failed updates on the older phone models with the 32-bit A6 processor.
The install process through iTunes remains the same as it has always been — following the connection of an iPhone to iTunes through a Lightning cable, users are given the option to update the device to the new operating system. AppleInsider has confirmed that the iTunes update installs properly on an iPhone 5c.
The iOS 10.3 update, released Monday, includes Find My AirPods, Apple File System implementation, and other improvements for developers and the App Store. Regardless of the source of the update, AppleInsider recommends performing a full, encrypted backup prior to updating to iOS 10.3.