Hey Michael, unfortunately as the code stands now it is not compatible with older firmware. The commit I linked above changed the command that is sent to the mount for guide pulses, so if your mount isn't moving during calibration or guiding, you'll either need to wait for a driver update to make this compatible with older firmware or update your firmware on the mount.
It appears the reason for the change is that iOptron is deprecating the older commands to do pulse guiding, so the driver was updated to use the new ones. Unfortunately, if you are on an older firmware, your mount won't recognize the new commands.
Can you provide the firmware you are on now? We might be able to make it backwards compatible by checking the firmware version.