title: C2DM Registration ID vs GCM Registration ID?
body: <p>I notice that Google has deprecated C2DM and changes it to GCM.
  Then, in its <a href="http://developer.android.com/guide/google/gcm/c2dm.html#client" rel="nofollow noreferrer">Migration docs</a>, it states:</p>
  <blockquote>
  <p>After receiving a response from GCM, the registration ID obtained must
  be sent to the application server. When doing this, the application
  should indicate that it is sending a GCM registration ID so that the
  server can distinguish it from existing C2DM registrations.</p>
  </blockquote>
  <p>For anyone have migrated C2DM to GCM, is the registration ID in different format for both services? Because it states</p>
  <blockquote>
  <p>the application
  should indicate that it is sending a GCM registration ID so that the
  server can distinguish it from existing C2DM registrations.</p>
  </blockquote>
  <p>Thanks</p>