Hi
@MissJ ... A few questions - just to get us on the same page:
1) What mobile device are you running the Go4 app' on?
2) Will the Go4 app' actually run on the mobile device? (i.e you can start the Go4 app' - yes??)
3) How is the mobile device connected to the DJI RC controller (short DJI cable on the side? or USB-A cable in the base??)
4) Have you checked the switch under the small flap on the side of the Mav' Pro to make sure that it is switched to 'RC' and not 'WiFi' ??
5) Did you have a fully functional drone & Go4 before the firmware update you mention in post # 1 above??