Government authorities that want to access a citizen's iPhone will find it harder thanks to a new Emergency SOS mode feature in iOS 11.If a user hits the power/sleep button five times in quick succession it will bring up a new screen that locks Touch ID.The feature follows increasingly complex legal wrangles over police attempts to get suspects to unlock smartphones protected by biometric security.In the US, police can force users to unlock their devices via a built-in fingerprint reader. However, they can't demand a passcode or password as this is covered by the Fifth Amendment, which protects individuals from self-incrimination. In the UK, meanwhile, police can't force suspects to unlock their device via fingerprint.When activated the Emergency SOS mode automatically calls the user's next of kin. The system also requires the iPhone owner to enter their passcode in order to revert back to normal, which could prevent thieves from taking advantage of an injured or unconscious person. Another safety update is the new “Do not disturb while driving mode”, which can detect when an owner is behind the wheel. It turns the iPhone screen black and stops calls and text messages. Users can set it to automatically reply with a note saying they are driving.