You can check which version you currently have installed in Settings within the app, near the bottom.
To update, please go here on your on each of your device(s) and click UPDATE to update to the latest version: https://play.google.com/store/apps/details?id=com.aadhk.woinvoice
If there is no UPDATE button, please follow these steps instead:
- Open the Google Play Store app .
- Tap Menu, then My apps & games.
- Find the our app in the list and tap Update.
For more details see: https://support.google.com/googleplay/answer/113412