Android alternative to GCM Push Notifications : <p>I develop a messenger application. To deliver messages used GCM and Websockets, when app in background websocket is closed and only gcm can push message to device.<br>
I tested my app on some devices and seems it works fine.<br><br>
But on the Play Market I have many comments about "messages not delivered when app in background". <br></p>

<p><strong>What is the best way to do that messages are always guaranteed delivered when app is background?</strong> <br> <br>
May be I need use background Service that always contains websocket connection? <br>
How it is done in Whatsapp messenger?</p>
