title: Update server endpoints while migrating to FCM
body: <p>The GCM server and client APIs are deprecated and will be removed as soon as April 11, 2019.
  My question is, what happens if the server endpoint is not updated post the dead-line. I already have apps that are using Push Notification on store and do not want to alter anything. Will the server be able to send the notifications with endpoint (gcm-http.googleapis.com/gcm/) after the mentioned date?</p>