title: Openfire Sending Push notification when user is offline
body: <p>I am using openfire 3.9.3 server and Android and IOS as client.
  I want to send messages via push notification to both clients when recipient user is offline. 
  And when push is sent sender should get message receipt.</p>
  
  <p>for this, i tried : </p>
  
  <ol>
  <li><p>making interceptor: In this, i didn't get any exception or message failure for which i can track.</p></li>
  <li><p>modify openfire code also. But i don't think it is a good solution.</p></li>
  </ol>
  
  <p>I just want to know that, is there any plugin for it or modifying the openfire code is the last solution for it?</p>