Here's my set up:
Airnotifier 3.x
Moodle site 4.0.3
Moodle customized app 4.0.2

When I send push notifications from Moodle to the app, there's no sound or vibration on iOS, on modern Android it works fine, but on older android, it doesn't have sound or vibration

I have access and have already tried it with an official Airnotifier from the Moodle team and everything works fine so I think this is a problem with 3.x version of Airnotifier.

Thanks in advanced