title: Unable to Build 3.1.3 Device on iPhone SDK 4?
body: <p>I just installed iPhone SDK 4, and i couldnt build app on 3.1.3 devices?</p>
  
  <p>it says the SDK 3.1.3 is missing, did apple remove the previous SDK?</p>
  
  <p>How do we test on the previous iPhone OS version?</p>