title: Difference between voip push and regular push when waking app from background
body: <p>I have a messaging service that I use for regular push notifications. For example, when one user sends a message, the other user receives a push notification with that message. I have noticed if the phone is on wifi and 3g / 4g, and the app is killed (and the screen is locked), the notification will be received. If the device is only on wifi and the app is killed (and the screen is locked), the notification is not received.</p>
  
  <p>My assumption is that in order to conserve battery, the device disconnects from wifi after a certain time, and that is why push notifications are not received.</p>
  
  <p>But when I use VOIP push notifications, the situation is different. Even if the app is killed and the device is on wifi (and the screen is locked), the notification will be received. So what does this mean? How is phone receiving this notification, if it disconnects from wifi?</p>
  
  <p>What am I missing here?</p>