Why does the Xiaomi Watch S4 vibrate but not light up when a notification is received?

By default, the Xiaomi Watch S4 is set to vibrate for new notifications without lighting up the screen. To view the notification, you can raise your wrist to wake the screen or manually press the power button to turn it on.
However, if you prefer the screen to light up with notifications, you can enable the Wake screen function.
To enable the Wake screen function, please refer to the following methods:
1. Open the Mi Fitness APP, go to [Device] >> select [Notifications and calls] >> enter [App notifications] >> toggle on the [Wake screen] setting;
2. Alternatively, you can go to the Settings APP on your watch and enter APP notifications to enable [Wake screen].