Working on Push notification setup in iOS 8 and older version.
How to enable remote push notification in ios sdk.
What is push notification ?
In iOS, apps can’t do a lot in the background. Apps are only allowed to do limited set of activities so battery life is conserved.
For example, maybe the user received a new tweet, their favorite team won the game, or their dinner is ready. Since the app isn’t currently running, it cannot check for these events.