Update The updated app runs more smoothly. I use it on my cell and Nexus 7 tablet.
Bug fixes - Turn off battery optimization
Go to Settings.
Go to Battery.
Tap 3 dots at top right.
Tap “Battery Optimization”.
Tap “Not Optimized” and change it to “All apps”.
Scroll down to find the app.
Tap on app listing.
Tap “Don’t optimize” and then tap “Done”.