<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="pl.pawelkleczkowski.customgauge">

    <application
        android:allowBackup="true"
        android:label="@string/app_name"
        android:supportsRtl="true">

    </application>

</manifest>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="pl.pawelkleczkowski.customgauge">

    <application
        android:label="@string/app_name"
        android:supportsRtl="true">
    </application>

</manifest>

Delete backup property from library Manifest
Delete backup property from library Manifest

The decision of allowing automatic backups of the application data is completely out of the scope of the library. 
Its presence causes conflicts when the app developer wants to deactivate it.