There are indeed two versions of the SHD that were released due to the streamer module becoming End of Life. We call the older generation of the SHD "neo2" and the newer generation "neo3". You will be able to tell the difference by the color of the USB host port near the RJ45. Neo2 uses black and white; neo3 uses blue.
There aren't sound quality difference between the two generations so if you own a neo2 unit, you do not need to rush for a neo3 unit :)