Apple on Tuesday stopped signing code for iOS 13.7, the last iteration of iOS 13 to be issued prior to last week's debut of iOS 14.
The halt of iOS 13.7 code signing comes six days after Apple pushed out the next-generation iOS 14 in a release that took the public — and developers — by surprise. With Apple no longer authenticating iOS 13.7 code, device users who upgraded to iOS 14 are no longer able to download or install the now out-of-date operating system.
The outgoing operating system version included support for Apple and Google's Exposure Notification Express system, which enables users to take advantage of the framework without downloading an app. Local health authorities are required to support the feature, though the update takes much of the burden off of users.
Apple routinely stops signing legacy code after the release of a new iOS build in part to protect customers from nefarious actors attempting to take advantage of newly discovered vulnerabilities. In addition to security, preventing users from downloading older code allows Apple to keep more iOS devices on the latest, feature-rich software.