How can I set my Base SDK?

When I try to set the Base SDK in Project Info, the only SDK that appears is iOS 4.1 and iOS 3.2.

How can I add additional SDK's so开发者_开发问答 I can support older users when my app hits the App Store?

You can select the deployment target in your project info;

Look for the iOS Deployment Target in the very same settings panel. Also, be careful about methods not available in earlier OS versions.

You've been tricked. Apple made the top visible Base SDK a nearly useless setting. Instead the useful setting is hidden where you have to scroll down to find it: the iOS Deployment Target, where you set the lowest level of OS which you want to be able to load your app.

Apple also removed any ability to determine whether you are using any API incompatible with an older Deployment Target OS other than keeping a device around which can run an old version of the OS.

So, ignore Base SDK (other than making sure it's set to a legal setting). Set the Deployment Target to what you want. And test on an actual device at the Deployment Target level.