The SALTO KS app exists for both your Mobile and Smart Watch.
The following devices are compatible for each:
Mobile App (SALTO KS App for the phone) works on Mobile Devices from Android Marshmallow (Android 6, SDK/API 23) and higher.
Wear OS App (SALTO KS App for the watch) works on any smart watches running Wear OS. The smartphone needs to have Android version 8 or higher.
In order to use your Digital Key in your Wear OS smart watch, your phone need to have Android version 8 and higher with API 26.