Cause
This error ("Your device isn't compatible with this version" when the device does indeed meet the install criteria) is a common Android device error with the Google Play store. There are numerous reports of this kind of error across Android forums affecting a variety of apps. The solution is generally some combination of clearing the cached data for the Google Play app and/or signing out, restarting the device, and then signing back in. Please try other Android devices as well, if available, to confirm that this should not be a general issue with the app and that it is rather isolated to specific devices.
Resolution
Here are the recommended steps to resolve this error:
Clear cached data for Google Play Store app & Google Play Services (Go to Settings > Apps or Application Manager > Google Play Services > Clear cache > OK).
Uninstall updates for the Google Play Store app (Go to Settings > Apps or Application Manager > Google Play Store > Uninstall updates > OK).
Uninstall updates for Google Play Services (Go to Settings > Apps or Application Manager > Google Play Services > Uninstall updates > OK).
Remove Google Account: Open your device's Settings app.
Under "Accounts," tap Google and then the account you want to remove.
Tap the Menu icon in the top right corner of the screen.
Tap Remove account.
Restart your device.
Install updates to the Google Play Services app.
Install updates to the Google Play Store app.
Add Google Account: Open your device's Settings app.
Under "Accounts," tap Add account > Google.
Follow the instructions to add your account.
If this does not resolve the issue, we recommend contacting Google Play support for further assistance with your device: https://support.google.com/googleplay/answer/7100415#contact=1.