Apple has stopped signing code for iOS 14.5, effectively blocking downgrades to the operating system following the release of iOS 14.5.1.
The halt of iOS 14.5 code signing comes about a week after the company released iOS 14.5.1, a minor update that contained bug fixes and patches for WebKit vulnerabilities that were being exploited in the wild.
With Apple no longer authenticating iOS 5 code, users who upgraded to iOS 14.5.1 are no longer able to download or install the now out-of-date operating system.
At the time of iOS 14.5's release, Apple also stopped signing code for iOS 14.4.2.
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.
The Cupertino company is currently beta testing its upcoming iOS 14.6 update. That point update isn't expected to contain major user-facing features, however.