In this version, you can buy the key to unlock the app on your watch.
This key will be sent on the next time that the phone communicates with your watch (e.g. when you press the button SEND).
Buying the key does NOT change anything on the Android app. It will just unlock the app ON YOUR WATCH.
How do you know if the app is unlocked: open the menu on the watch (long press UP or MENU button) and scroll until the last option. If you see UNLOCK PRO, the app is NOT unlocked. Otherwise, it is unlocked!
If you have already unlocked the app in a different way, you don't need to buy the key.
Contact the developer if you have any question.