Hello,
I encountered this issue today on a fresh install on a Pixel 4a (yes, I know it's unsupported).
For supported devices:
You should have a toggle in the Boursobank app settings to disable "Play Integrity Checks" (or "Check Integrity")
For older/unsupported devices without the toggle:
The workaround that worked for me:
- Download the app (from Play Store or Aurora Store)
- Go to Settings → Apps → Google Play Services → Disable
- Go to Settings → Apps → Boursobank → Storage → Clear Storage
- Open Boursobank and login (the integrity check error should not appear)
- Once logged in, you can re-enable Google Play Services
Hope this helps!