in the iOS 12.5.8, iOS 15.8.6, and iOS 18.7.4 release notes, Apple says:
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The implications of this update are insane and scummy tbh. essentially anyone on a device that can support iOS 26 will be forced to update to a later version by January 2027 or apple services will stop working. And you can’t update to these newest versions with latest certificate *unless* you have a device that only goes up to 12/15/18 geez.
So if you’re staying behind purposefully on say iOS 18, even the last one you could grab 18.7.3, you only have a year before you can either OTA to some extended support EOL iOS 26 security update or presumably iOS 27 by then since we are talking about Jan 2027 deadline
This update extends the certificate required by features such as iMessage, FaceTime, and device activation to continue working after January 2027.
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The implications of this update are insane and scummy tbh. essentially anyone on a device that can support iOS 26 will be forced to update to a later version by January 2027 or apple services will stop working. And you can’t update to these newest versions with latest certificate *unless* you have a device that only goes up to 12/15/18 geez.
So if you’re staying behind purposefully on say iOS 18, even the last one you could grab 18.7.3, you only have a year before you can either OTA to some extended support EOL iOS 26 security update or presumably iOS 27 by then since we are talking about Jan 2027 deadline