When I transferred the test program to the PLC and trigger the GetFWVer input it did respond the firmware version. But when I power off the PLC and then power on again I got what you observed - i.e. the STATUS(5) returns a zero.
So I think there is a bug with the STATUS(5) - the data was set only when there is a query of the firmware version from the hostlink command. This will not be very useful as an automatic indication of the firmware version to the program which was the original intention. This is now reported to the FW development team for future fixes. So this function should not be used
If you still want to use this feature one way is for your program to copy the STATUS(5) result to a FRAM address space during 1st.Scan when it determines that STATUS(5) returns a non zero value (when the program is first transferred to the PLC and a reset is trigger). The FRAM space is then used as indication of the firmware version.
E.g. in an INIT function triggered by a 1st.Scan pulse:
IF STATUS(5) >= 78
SAVE_EEP STATUS(5), 1000
ENDIF
The firmware version is then stored into the FRAM address 1000 which can be used as an indication of the firmware version.