title: Building a project in Xcode5.1 that was modified in Xcode 6 GM for testing older versions of iOS
body: <p>My app has been supporting at least iOS6 using Xcode5.1 storyboard.</p>
  
  <p>After I did several work in Xcode 6 GM, I need to test on iOS 6 Simulator.
   Xcode 6 GM does not have iOS 6 Simulator.So, I opened my project in Xcode 5.1.</p>
  
  <p>But It fails to build. I cannot even open the storyboard in Xcode5.1.</p>
  
  <p>At the navigation pane, it says </p>
  
  <pre><code>Main_iPhone.storboard
  Interface Builder Storyboard Compiler Error
  The document"(null)" requires Xcode6.0 or later.
  </code></pre>
  
  <p>And when I click it, a prompt appears </p>
  
  <pre><code>The document "Main_iPhone.storyboard" requires Xcode 6.0 or later.
  This version does not support constraints to layout margins. Open this document with Xcode 6.0 or later.
  </code></pre>