Does the Xiaomi Watch S4 support unlocking the phone with Bluetooth?

The watch supports unlocking the phone. This function currently supports Xiaomi phones with system versions of MIUI 12 and above. When the phone and watch are connected via Bluetooth, the watch unlocking is a one-to-one binding between the watch and the phone. Within a safe distance, the watch can be used as an identity ID to replace the input of the unlock password or pattern, which greatly improves the convenience of operation while ensuring security.
To configure unlocking the phone with the watch, please refer to the following details:
1. Go to the [Mi Fitness] APP >> [Device] >> [Security] >> [Unlock phone] >> set the password and confirm on the watch;
2. After the lock screen password is set, confirm the unlock on the watch to successfully bind. You can choose the unlock distance (close, moderate, slightly far). If you want to unbind the watch, you need to disable the Bluetooth device unlocking function in the phone system settings. Take the Xiaomi phone as an example: [Settings] >> [Fingerprints, face data, and screen lock] >> [Unlock with Bluetooth device].
Note:
The function of unlocking the phone needs to be used with Xiaomi phones running MIUI 12 or above, so if the model and system do not match, the APP will not display the [Unlock phone].