title: iPhone - How to determine the deployment target iOS version of an existing project
body: <p>I have an existing huge iOS project, set for iOS 5.0 target by default. But I'm pretty sure that it is also 4.?.? compliant. </p>
  
  <p>How may I know the minimum iOS version my app can be targeted to, without having to compare the whole code word by word with the iOS documentation to know for each method/constant/... the iOS version it was introduced, and at the end, know what minimum iOS version I can target ? That would take weeks !</p>
  
  <p>(XCode does not help... Setting the iOS target to something lower that iOS 5 never raises any warning nor error when compiling, so I don't know for example, which methods are only available for iOS 4.2 when setting target version to iOS 4.1...)</p>