title: iOS Support ad vs ad-free versions of same app
body: <p>I have a paid app on appstore that is not returning much revenue.<br>
  So I have made a new version that is free instead, but it includes ads.
  Now two questions.  </p>
  
  <p>1) I want to make an alert "If you want ad-free version press here". Here the user will be informed of the cost (1dollar) and then they can "register" and get adfree version. Now the million dollar question is: is that done using an "inApp purchase"?  </p>
  
  <p>2) How do I "justify" for the users who have bought the app before? now it is free maybe if they contact me I can "register" them in the inApp??</p>
  
  <p>Thanks in advance. </p>
  
  <p>EDIT:<br>
  1) How do i check inside my app code if user has bought "inApp purchase"?<br>
  2) Does anybody know a way to check if a user is an "old user that has paid before app became with ads"?</p>