Unfortunately our core team do not have the resources here to help people use the open source code version to build custom apps. We provide a service where we can customise the app for anyone who needs it including the Push notifications (Airnotifier) service management. This service helps fund the improvement of the app in general: https://moodle.com/mobileapp/

I’d recommend you to check the documentation links that are available in the Forum main page or hopefully somebody else in this forum will be able to help you.