public void unregister() throws IOException {
// When setting an empty GCM id, the Signal-Server also sets the fetchesMessages property to false.
// If this is the master device, other users can't send messages to this number anymore.
// If this is a linked device, other users can still send messages, but this device doesn't receive them anymore.
accountManager.setGcmId(Optional.<String>absent());
public void unregister() throws IOException {
// When setting an empty GCM id, the Signal-Server also sets the fetchesMessages property to false.
// If this is the master device, other users can't send messages to this number anymore.
// If this is a linked device, other users can still send messages, but this device doesn't receive them anymore.
accountManager.setGcmId(Optional.<String>absent());