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

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

    </application>

</manifest>

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

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

    </application>

</manifest>

Remove android:allowBackup="false" from library manifest
Remove android:allowBackup="false" from library manifest

Currently I get a manifest merging error because my app sets android:allowBackup="false" and this conflicts.

Library projects shouldn't be setting this.