- Normally, an inactive iOS app will not receive in-app messages until the user specifically wakes up the app.
- Your server using this feature sends a push notification which will be received on the iOS device.
- The mobile user views the notification and the app is (re-)activated.
- At that point, a connection to PubNub receives queued messages that were published to the subscribed channel while the app was inactive.
Note that published messages are stored on PubNub servers for delivery only for a limited time (less than an hour) and then deleted. To access older messages, use History (Storage & Playback) feature to access messages stored for up to 30 days (or forever in Global Cloud accounts).
On non-iOS devices (e.g. Android, Blackberry and others), PubNub is able to receive messages while the app is in the background. On Android, PubNub can both wake up the app and even launch it if it isn't open!