When we install an iOS SDK from Apple, it's a unique experience. Apple has decided that they only want us to have the latest SDK on the most recent version of Mac OS X. This is far from the typical experience you may have had with other platforms, or multiple SDKs being installed simultaneously is the norm.

It is possible, and supported by Apple, to have multiple SDKs, but it is not very practical. For example, we could do the following:

But that is not what Apple want us to do, and really, it's not what we want to do either. There may be some exceptions, but for the most part, we want to jump on the Apple bandwagon and recognize that deploying our game using the latest and greatest SDK is indeed the correct thing to do.

So, what we want to do is this:

The reason for this cavalier attitude is that the version of iOS on which your game runs has little to do with the iOS SDK that you are using. The version of the iOS on which your game runs is called the Target Platform, and it's perfectly acceptable to have a target platform of iOS 3.0 with the iOS 4.3 SDK.

It took the folks at Unity3D a while to catch on to, and fully support, this idea. Prior to Unity3D, you would need to go into your project settings after each iOS SDK install and update them to reflect the latest version of the SDK (or use Time Machine to restore the removed previous SDK).

Thankfully, those days are gone. Now, setting up our Unity3D project so that it automatically uses the latest SDK, which for the most part is what we want to do, has been greatly simplified.

What we need to do in Unity3D 3.x is this:

And that is all there is to it. Now, when we install the latest iOS SDK version and re-build our project, the generated XCODE project should be correctly configured and built. It doesn't get any easier and it looks like the following screenshots: