The V2 software was the first major update to our tracking software, hence the name "version 2". With the release of the Orion software, our tracking software is able to better calculate the orientation and position of hands not visible by the sensor. Our older software attempted to do so but was not as accurate.
There is currently only one version of the Leap Motion controller hardware available. All of our improvements have been done through software updates.
You may have more luck with more technical questions in our developer section of the forums. I will move this thread over there for you.