What is a VoIP push?
VoIP push notification is a background push that generates no alert or sound, and used to wake up an app and pass it the information about the incoming call. The app should display a local notification to users, and the call is established when the user swipes the notification.
Here is our documentation regarding the implementation of VoIP pushes:
For Xamarin users we advise trying Xamarin's MonoTouch.PushKit, which is pretty much similar:
You can only create a VoIP certificate in production mode, not development mode. Therefore, in Pushwoosh iOS app configuration you should always use Production gateway for VoIP certificates.