title: How to get notified when our app is uninstalled in iOS
body: <p>We are developing an iPhone application that allow users to send messages to others via Apple Push Notification Service when the target user have installed our application or SMS when haven't.</p>
  
  <p>We want to get notified immediately when our app is uninstalled so that we can decide how to send the message to the target user.</p>
  
  <p>We find the APNS feedback server have a long time delay that doesn't agree with our requirement. So we use another way: when our server recorded the target user have installed our application, we send him message via APNS, if he haven't read the message in 30 minutes, we believe that he has uninstalled the application, so we send the message via SMS.</p>
  
  <p>Is there any way better?</p>