title: UIStackView before iOS 9.0
body: <p>I recently upgraded XCode to the latest Version 7.0 beta 3 (7A152u).</p>
  
  <p>I am using Swift for building an iPhone app and when I try to use a Stack View in Main.storyboard I get the error "<strong>UIStackView before iOS 9.0</strong>".</p>
  
  <p>I thought with the upgrade to Xcode 7 beta 3,  I have iOS 9. Please correct my understanding as I am quite new to Swift development.</p>