89b23736_are_Upgrades___Doppler_Systems__Notes
[Revision] 2.17 [Release Date] 2/12/2013 [Notes] 
Fixed bug that caused the direction finders to register improperly on a radio modem network when using the direction finders on a radio modem network without computers at each site. No need to upgrade unless you are using the DF on a radio modem network.
Firmware Upgrades | Doppler Systems
Notes