Upgrade iOS application to newer OS?

Question

I am a little curious what happens in the following situation. You have an existing app on the iTunes store (with customers) that uses iOS4, you then release an update to the app that uses a newer iOS.

• folks that have upgraded to the "newer iOS" will get the update.
• What will happen to those that have not updated, will they still be able to use their old iOS4 version?

Answer 1

Your "deployment target" is what matters. Setting the deployment target allows your app to set it's minimum required OS version. Many developers like to set that as far back as possible, unless your app depends on a features only available in a new iOS version.

Lets say you have an app compiled with the iOS 4 SDK and set 3.0 as the deployment target.

• Users with iOS 3 or iOS 4 (and iOS 5) can download your app and use it.

Now you release an update compiled with the iOS 5 SDK and set 4.0 as your deployment target.

• Users with iOS 4 or iOS 5 can download or upgrade your app and use it.
• Users with iOS 3 that have purchased your app already cannot upgrade, but they can continue to use their existing installed version.
• Users with iOS 3 that have not purchased your app yet will now have no way to do so.

Apple will only keep exactly one version of your app on the app store.