title: What is suitable ios version for the current Three20 sdk?
body: <p>I try to test one of my app in which I used Three20 sdk.
  It worked on ios 4.2, 4.3.1 ipad
  but exited immediately when started on ipod touch with ios 3.1.3</p>
  
  <p>I just wonder what is suitable ios version for the current Three20 sdk?</p>
  
  <p>Welcome any comment</p>