Push notification via Parse are working great on pre-Android 6.0 devices, but for some reason push notifications are not working for me on Android 6.0 Marshmallow Developer Preview 3. I get a Cannot use GCM for push because the app manifest is missing some required declarations. Please make sure that these permissions are declared as children of the root even though all the necessary permissions are supplied.
I have outlined the issue in its entirety on StackOverflow.