title: iOS - In App Purchase - auto renew subscription - How to get notified if the user cancel or auto renewable subscription?
body: <p>I am working on an app which has our own user database and cross platforms subscription.
  and my questions are:</p>
  
  <p>pre-condition: in iOS, user did login with username and did auto-renew subscription.</p>
  
  <p>1.if user deleted the app, will it cancel the auto-renew subscription for the app?</p>
  
  <ol start="2">
  <li>if user cancel the subscription from settings or from itunes, how do we know which user canceled the services?(I dont have game center id). I would like to inform my server that this user canceled subscription.</li>
  </ol>
  
  <p>basically, how do we know a user did auto-renew or canceled the subscription without opening app.  Is there any unique id in apple's receipt which we can get to validate the user id.</p>
  
  <p>Thanks.</p>