What happens to existing iOS app when I update?

I have, after many months of work, finally got my app updated for iOS4.

The first release was complied for iOS3.2 and has been in the AppStore for a while, I was very impressed to see it continued to work and be downloadable for iOS4 users all this time, even though my version failed to compile for iOS4.

However, now I've got the new version (complied for iOS4.2) waiting for review - I'm unsure what will happen to the existing app! If it is used overwritten, what will people with old versions of i开发者_运维技巧OS see? Am I closing the door to anyone without iOS4.2+?

Many thanks

Ben.

p.s. apologies if this has been covered - I did look and failed to find :-)

When you specify the minimum OS required in the bundle, that filters what users will be notified of the upgrade. So users of your app that have yet to upgrade the underlying OS will not get pushed the update.

You can actually specify the target OS Level to an earlier version. The app will be allowed to install on that and any newer version. Generally, Apple is very good about forward-compatibility.

As Peter said, you probably don't want to compile it to only run on 4.2. If you added features that use newer versions of iOS, you can actually do a check prior to calling the method (I've done this with gesture recognizers) to ensure that the running OS version is capable. If you don't validate the OS, the app will simply crash on users with too-old operating systems, which could cause Apple to reject it.

Also, 4.3 is almost out, so you might as well wait a week :)

If your app only supports 4.2+, then only users with a device with 4.2+ iOS will be able to install and use your app. The version currently on the store will be overwritten. In short, yes you are "closing the door" to anyone with a lower version iOS.