Inactivity reboot" effectively puts iPhones in a more secure state by locking the user's encryption keys in the iPhone's secure enclave chip.

Last week brought reports of police officials warning other departments that iPhones being stored in evidence for forensic examination were rebooting themselves. 404Media writes that security

With iOS 18, Apple introduced a feature that causes the iPhone to reboot every three days, security researchers have confirmed (via TechCrunch). In

Apple’s latest iOS 18.1 update brings a fresh security feature aimed at protecting user data if an iPhone is lost or stolen. The new Inactivity Reboot function automatically restarts an iPhone after 72 hours of inactivity,

However, the explanation is actually much simpler. Referring to the feature as an "inactivity reboot," AppleInsider says that this reboot timer isn't based on network connectivity or the phone's charge. Rather, the reboot simply occurs after a specific length of time -- around 96 hours.

404 Media reported that iPhones stored by police in evidence were rebooting themselves, and it turns out it’s all due to a new Inactivity Reboot feature shipping in iOS 18.1. First reported by security researcher Jiska Classen, this new feature reboots your iPhone if it has gone unused for at least four days.