Lumia 950 release ring, GCM reinstalled without any tweak.
Connection is more stable, since this morning only lost connection twice. After a Lumia reboot the connection was reestablished
Notifications: OK/2 they usually work but with a delay.
Music controls: Usually they work as expected (play/pause, skip, volume) however sometimes they refuse to work;
Weather: No problem;
Find my phone: OK
Only have the new version installed for 9 hours so it's premature to say anything.