Only receiving Notification, not call of upcoming calls

Thanks for the additional context. I think it depends on the situation, you can see the list of ‘exceptions’ to the rule here. In general I don’t think there is an easy way around this without explicitly granting:

<uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW" />

Which is why our new sample removed it. So I would say no there isn’t really a way to get around it.