There are a lot of big changes in iOS 18, but there is one you may not have noticed. A security researcher noticed (via TechCrunch) that iPhones running the new software have a special security measure that automatically restarts them after 72 hours of inactivity.

Security researcher Jiska Classen posted a time lapse on X showing this feature in action. In this time lapse, an iPhone running iOS 18.2 beta is locked and left for three days. It is then shown to be a full reboot, as the phone's unlock screen clearly states that a passcode must be used after the reboot.

As Classen points out, iPhones become much harder to break into after a reboot; it does not matter whether the iPhone is in the hands of a thief, a law enforcement agency, or someone else entirely. The forensic tools used are much more difficult to penetrate than a typical unlock screen, and Classen points out that this is due in part to the fact that the “before first unlock” state of the iPhone locks the encryption key within the Secure Enclave Processor. He points out.

Interestingly, we have already heard that this feature is causing problems for law enforcement. Police have theorized that iPhones with iOS 18 are secretly communicating with each other, causing spontaneous reboots when other phones are disconnected from the cellular network.

It turns out that it was not very technical; iPhones are simply programmed to reboot if left dormant for too long. These reboots seem to happen regardless of whether the iPhone is grabbing a signal or not. In other words, it is coded into the phone itself and not prompted by an outside force.

Magnet Forensics confirmed this feature themselves, noting that iOS 18 initially set the restart time to 7 days. However, iOS 18.1 shortened the countdown to 3 days and noted that there are no prompts or warnings indicating that an automatic restart is approaching.

For the average person, they will not experience automatic lockouts often. They use their iPhones every day, which likely means that the timer cannot count down to completion. Still, in the unlikely event that it does lock up before the battery runs out, it will only leave you mildly annoyed because you will have to enter the passcode again.

But what about for those trying to gain unauthorized access? Suddenly, they have a much harder time accessing your data. That said, the three-day timer means that both criminals and law enforcement still have time to crack your phone if they are proactive.