The iOS 11.4.1 update includes a new security feature that restricts the way USB accessories can interact with iPhone and iPad devices. If the phone has not been unlocked within the last hour, iOS will disable the Lightning port so USB accessories cannot communicate with the device. After unlocking, any accessories will stay connected.
USB power chargers are not affected, but some USB accessories that provide power may not charge the device until the device has been unlocked. Apple has detailed in a new support article exactly what this means for users ….