Apple on Tuesday ceased signing code for iOS 13.6.1, effectively barring users who updated to the latest iOS 13.7 operating system from downgrading.
Issued last week, iOS 13.7 includes new capabilities for Apple and Google's coronavirus Exposure Notification system. Specifically, users can now opt in to the program without first downloading an app developed by their local government.
In addition, the new Exposure Notification Express feature enables Apple to present health instructions to users if it is determined that they were potentially exposed to the virus. This is accomplished without a third-party app, though data sharing with public health authorities is required for full functionality.
The outgoing iOS 13.6.1 arrived in August to fix a number of minor bugs including a thermal management issue that could cause an iPhone's screen to display a green tint. Also remedied was a problem with Exposure Notification alerts, as well as an issue that prevented the deletion of unused system files.
Today's stoppage means users can no longer download the out-of-date operating system from Apple's servers. Apple regularly ceases signing of older code to prevent installation of past iOS versions following the release of a new variant, a practice that keeps users safe from new threats and ensures devices are running the latest feature-rich software.