With iOS 15, you can still track your iPhone through the Find My network even if the device is powered off. It seems that with iOS 15, even when the phone is turned off, it is not completely ‘off’; it remains in ultra-low power mode and operates like an AirTag, allowing any nearby iOS devices to receive Bluetooth signals and relay its location.
This also means that if your iPhone runs out of battery, you still have a chance to find its location for a few more hours. In fact, Apple states that the location tracking feature will even continue to work if the phone is reset to factory settings when Activation Lock is enabled.
“Locate your device using the Find My network even if they are turned off. This can help you identify the location of a lost device if the battery is low or may have been turned off by a thief,” Apple said. Interestingly, Apple typically does not advocate using Find My features for anti-theft purposes.
Apple notifies users about this new feature with a warning dialog when the iPhone first updates to iOS 15 and the battery is running low.
If you want to actually turn off your iPhone, you can change the settings and completely disable the Find My network mode.
Source: AppleInsider