title: Users are not reciveing GCM push notifications after updating app
body: <p>Currently, my android app is live on play store.Currently, I have integrated GCM in it and uploaded it on play store. The problem is newly downloaded users are getting a notification on the app but previous users those who have updated the app to current version are not receiving notifications.
  Is there any configuration for GCM I have to do it on play store?</p>