question about firmware Firmware Version Property

[redavenger]

hey guys
can someone explain what the Firmware Version Property means.
i have a couple of DS-2CD2355FWD-I
now the original firmware on the camera is version V5.5.51 build 180408 with
firmware version property C-R-G1-0
now i upgraded one of the cameras to firmware version v5.5.52 and it changed the firmware version property to B-R-G1-0

so what does this change from C to B mean?

 

[redavenger]

only thing i can think of its something to do with C meaning its factory only firmware??
also is there any way of downloading the firmware from the camera?