On your Watch

1. Open the app on your Apple Watch

2. Scroll down and click 'Settings'

3. Scroll to the bottom and find the string of numbers - this is the version number
   It will probably look something like "V 1.25.0 (1)"
    

On your Phone

1. Open the app on your iPhone

2. Tap the "Settings" tab

3. Tap "Help & Support"

4. Look at the bottom for the version number
   It will probably look something like "App Version: 1.25.0.1 (Phone), 1.25.0.1 (Watch)