This wallet is a very stable, secure and alternative wallet for Android.
This SPV wallet is compatible with Android Q (10), 9.1 and older. Some Android systems require you to disable Google Play Protect to install the wallet. You must allow Storage and Camera(If you want Camera QR code) permissions to CMM Electrum. Syncing the blockchain headers will use 300MB of data.
You should connect to wifi and allow background permissions to allow for a fast sync. It will only need to sync one time and may take hours to days depending on your internet connection and how long the application is open. It will sync in less than an hour with the proper permissions.