title: How to create in-app purchase to upgrade from free version to paid version android
body: <p>I have two version of my app</p>
  
  <ol>
  <li>Paid Version</li>
  <li>Free Version</li>
  </ol>
  
  <p>Now in free version I disabled some features that are available only in the paid version.
  So what i want is when user taps on any of those disabled features, the in-app purchase window should pop up and when the transaction completes the free version of the app should get replaced by the paid version.</p>
  
  <p>Can you please tell me what would be the right way to do that.</p>