Updating application icon Badge in iPhone 3.0, when application is not running

I have an application, which lists number of IM sent by any of my friend using my application. And application icon show number of unread IMs to me. If my application is running in foreground, I can update badge by calling web service every 1 minute which wi开发者_如何学编程ll return number of unread IMs. Suppose, if the person is using iPhone3.0 and application is not running, how can i update the badge? Push notification without alert, but with just number of unread IMs as badge number will work?

Please advice, Thank you.

Yes if the user enables push notifications and allowes it for your app then you can use them to just adjust the badge counter.

At last, we found the problem, the problem is passing badge parameter as string in JSON payload, Now we are sending it as number, so even when the application is in background, badge getting set properly. Thank you for your all help.