A hidden feature in iOS 18.1 will automatically reboot a locked iPhone when it is asleep but hasn't been unlocked for a while, presumably as a security measure.The feature has been identified as an "inactivity reboot," and is similar to a feature found on Macs. The Mac version, known as "hibernation mode," saves the state of the device to disk when put to sleep, in case the power fails or the battery runs out before the user can return to the machine.By flushing the last state of the device, iPhone users are better protected from forensic searches by law enforcement or other entities. The change also makes it more difficult for anyone to break into the device using brute-force or other methods.The reboot timer is not reliant on charging or network functions, and is only tied to inactivity since the last unlock. This means the reboot will take place after a period of time, even if network connections are not maintained. Continue Reading on AppleInsider | Discuss on our Forums