How do I Ensure my Application's iOS Deployment Target will be Usable for that SDK?

I would like to set my iPhone App's iOS Deployment Target to the minimum possible SDK, which appears to be iOS 3.0 in Xcode version 3.2.6. Thus far, the base SDK I have been running against has been the latest (iOS 4.3). How can ensure that I am not using any newer features (i.e. since iOS 3.0) in my code, and that the appl开发者_如何学Pythonication will not crash for the older iOS versions? Do I just need to find and install the older iOS SDK? If so, where may I find these version controlled SDKs?

Thanks, Jeremy

You could try to run it on a device with the older sdk (we keep devices around with 3.1.3 for instance). However, you won't be able to find a downloadable version of the old OS from Apple.

If you don't have a versioned device around, the best way would be to look at any "suspicious" pieces of code that might have new features and make sure they are available in your base OS version (using the class references)

Yes, it's a bad system, but now you can start to keep old sdks around (i always make a copy onto a local storage device before I install a new version). As for restoring your device: I think you have to have made a backup at some time (i'm not 100% sure). But if you could I think it would be in organizer on Xcode and I guess you could check in iTunes too.