What happens to running iOS app when it gets updated from appstore?

Question

Imagine you have a running iOS app. It suggests you to go to AppStore to update itself. You press the button, go to AppStore, update the app, then return to the running(?) app.

What happens next?

Would your app be killed on update and restarted on return? If that, when it would be killed? When update starts or finishes?

Is there any possibility for you to return to the app when it is still with the old version during the update (highly undesirable, though)?

Answer 1

The app will quit when the user begins the update, and will not autolaunch on its own. But, you can make sure that current work/gameplay/etc. is saved by saving it to disk/cloud/defaults either when the user sends the app to the background or when the app terminates. Both of these situations can be handled by using the appropriate parts of the UIAppDelegate protocol (and making the changes to your app delegate.m file).