From June 2009 VM profiler systems were upgraded to a new generation electronics and hardware/firmware setup. Since the entire survey fleet uses auxiliary sensors for vessel speed and heading correction, the “Bottom Tracking” functionality were removed from the latest version of the firmware. The bottom-tracking functionality is only available for systems produced before June 2009. This is main boards with board numbers less than 1000 and firmwares of version 1.xx or 2.xx

The new sensor firmware, as well as the "old",  will work with SurveyVM version 1.42 and later.