If I install SDK 4.0 of the iPhone OS will I still be able to create a non 4.0 iPad app?

If I install SDK 4.0 of the iPhone OS w开发者_开发百科ill I still be able to create a non 4.0 iPad app?

I would ideally like to submit a iPad app in the next month but am also hoping to develop a 4.0 iPhone app is it possible to use the 4.0 SDK to create 3.0 iPad apps or am I going to need to computers?

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You do not need two computers. You will have to install the two SDKs in two different directories. So far, it's always been the way that beta releases of the SDK were not meant (and not allowed) to generate apps for distribution.

But in the installer, just select another new directory and then install the second SDK there. That's all there is to it.

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So far Apple has always provided a way to create Applications compatible to older versions of iPhone/iPad OS. The SDK installer will install the SDK in a version specific subdirectory. Additionally there is a "Current" directory hardlinking against the newest version. The old versions will still be available.

XCode will let you select an iPhone OS Version in the build settings and automatically figure out the correct SDK version/directory, so there's no need to fumble with paths or include directories.

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Build against the latest SDK and set your "deployment target" to a lower version. If you use new API calls (available in the SDK but not in the deployment version) check at runtime before calling them.