About fingerprint unlocking:
? Fingerprint unlocking is a screensaver unlocking software, which uses the user's fingerprint data for record verification. In addition to using fingerprints to unlock, you can also set gestures or nine squares to unlock. It is described as "a system for wireless matching and communication between devices using biometrics". These biometric features can include fingerprints, facial recognition, iris scanning, voice, etc. When users inject these data into different devices, data transmission will become simpler and safer.
Why don't 4S and old devices have fingerprints to unlock?
On August 3rd, 20654381,Apple applied to the US Patent and Trademark Office for a fingerprint unlocking patent, which was better than that of iPhone. 5S was released one year earlier. IPhone4S and other models released earlier than iPhone5S have not been applied because Apple has not fully mastered the fingerprint unlocking technology and patent restrictions.