The remote audio stops playing when minimizing the app. Also the local mic doesnt get sent to the remote partner when the app is minimized.
I also called the methods webex.getPhone().enableBackgroundConnection(true) and webex.getPhone().enableBackgroundStream(true).
We also used the sdk on iOS and there we just had to configure the app enabled background modes and it worked.
When sharing the screen from the android device the remote audio keeps playing and also the local mic gets sent to remote.