title: Could iOS Kill an App in the Background?
body: <p>While the device is powered on, is it possible for iOS to automatically terminate my app (calling <code>applicationWillTerminate:</code>) while it's in the background?</p>
  
  <p>I'm also curious what happens in two other cases, three in total:</p>
  
  <ol>
  <li>Device is powered on</li>
  <li>Device is powered off</li>
  <li>Device loses battery</li>
  </ol>
  
  <p>I'm asking because I want to know how often <code>applicationWillTerminate:</code> is likely to get called. I want to know this because that's where I'm registering for remote notifications. And if there's a failure sending the device token to the server, I want to know how likely it is that that method will get called again (i.e., retry sending the device token to the server).</p>