Apple has stopped signing recent iOS updates for several older iPhone models, preventing users from installing them. These updates, including iOS 12, iOS 15, iOS 16, and iOS 18, were released earlier this week. The move blocks installations even if the updates still appear in the Software Update settings. The purpose of these updates was to maintain core system services and address an expiring security certificate.

This decision impacts various iPhone and iPad models, including the iPhone 8, iPhone X, and several iPad generations. Apple hasn't disclosed the reason for this action, but it often pauses updates to fix bugs. A telecommunications company in Australia, Telstra, is investigating a problem that prevents some older Apple devices from connecting to their network and making emergency calls, which may be related.

The updates addressed issues with expiring security certificates impacting services like iMessage and FaceTime. Without these updates, functionality would cease after January 2027. This decision is likely due to connectivity problems. iOS 26.2.1 remains available, suggesting it is not affected. Apple may release revised builds once the issues get resolved.

This situation underscores the ongoing support Apple provides for older devices. While these updates are meant to keep older iPhones functioning, in this case, a problem has arisen. Users of affected devices should delay the update until the issue is fixed. We can expect further announcements regarding this issue from both Apple and Telstra.