Apple replaced Touch ID with Face ID in the iPhone X, a system that is said to have a far lower false positive rate compared to Touch ID, making it an ideal biometric authentication system upgrade for the iPhone. The use of the TrueDepth camera array also means that there is no need to place a fingerprint reader on the front of the iPhone, an addition that prevents the use of an edge-to-edge display and also introduces an element to an otherwise clear display when the iPhone is turned off.
