Hello Barry,
I can assume you are located not in APAC region, so upgrade is not mandatory required.
Please find more information on following link:
http://community.cambiumnetworks.com/t5/ePMP-2000-and-1000/GPS-Firmware-Upgrade/td-p/34553
There is no known issues with the lates GPS FW, but upgrade takes up to 10-15 minutes.
Thank you.