- Open Play Store
- Go to the Menu
- Tap 'My apps & games'
- Find WhatsApp Messenger within your 'Installed' apps
- Tap the app
- Hit 'Read more' and scroll to the bottom
Under 'App info,' if it says you have version 2.19.134, good news! Your phone is protected.
If you have an earlier version, for example 2.19.133, you need to update.