title: What kind of push notification approach is appropriate to use for Android 2.3.3?
body: <p>I want to implement a push message system inside my application and have been searching for a push service in Android.</p>
  
  <p>I found several different approaches, and the one that caught my eye was Google's GCM, but it seems it's not available for 2.3.3, and I would need to upgrade to API level 20. This means loosing a huge amount of users just because Google doesn't want to support historic versions of Android.</p>
  
  <p>Can anyone tell me what the best approach is for implementing push notifications in 2.3.3 or above?</p>