NMEA GPS unit not working in 4.4

Hi all,
Using NMEA (non ublox) GPS unit and upgraded to 4.4 to get new HD fonts in OSD with DJI WTFOS.
GPS unit works fine in 4.2, but will not work in 4.4 (and 4.3 for that matter). Any help is greatly appreciated.

4.4 can support nmea receiver. You may need to check your hardware connections first.

Need more info. What GPS? What autopilot? Log file?