title: New MessagingStyle on API < 24
body: <p>I just stumbled upon the new <code>MessagingStyle</code> described here: <a href="https://developer.android.com/guide/topics/ui/notifiers/notifications.html" rel="nofollow">https://developer.android.com/guide/topics/ui/notifiers/notifications.html</a> (last paragraph)</p>
  
  <p>I investigated further and found such a class also as a <code>NotificationCompat.Style</code> variant.</p>
  
  <p>This is the code I tried:</p>
  
  <pre><code>public class MainActivity extends AppCompatActivity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          ((NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE))
                  .notify(123, new NotificationCompat.Builder(this)
                          .setContentTitle("Test")
                          .setSmallIcon(R.mipmap.ic_launcher)
                          .setContentText("4 new messages")
                          .setStyle(new NotificationCompat.MessagingStyle("Me")
                                  .setConversationTitle("Team lunch")
                                  .addMessage("Hi", 123, null) // Pass in null for user.
                                  .addMessage("What's up?", 234, "Coworker")
                                  .addMessage("Not much", 345, null)
                                  .addMessage("How about lunch?", 456, "Coworker")).build());
      }
  }
  </code></pre>
  
  <p>This is basically just the default Activity generated when creating a new project and the sample code taken from the linked website.</p>
  
  <p>Now my problem: The extended style is not shown on APIs below 24. I tested on a device with API 23. When running on an emulator with API 24, it works.</p>
  
  <p>The <a href="https://developer.android.com/reference/android/support/v4/app/NotificationCompat.MessagingStyle.html" rel="nofollow" title="documentation">documentation</a> states:</p>
  
  <blockquote>
    <p>Helper class for generating large-format notifications that include multiple back-and-forth messages of varying types between any number of people. 
    If the platform does not provide large-format notifications, this method has no effect. The user will always see the normal notification view. [...]</p>
  </blockquote>
  
  <p>But versions since KitKat do provide large-format notifications.</p>
  
  <p>Is the documentation not clear enough or am I doing something wrong?</p>