Your newest MS170 is estetically identical to the one we've had here for a year or so. If it's made in China (like the ones we have here) chances are Stihl is simply building the same saw for both the European and US market in the same factory and with the same components with nothing more than different carbs and perhaps mufflers to comply with different emission requirements.
I don't know about the US market, but here the 170 has never sold well, so chances are the lag in the update may be due to Stihl wanting to get rid of unsold stocks before introducing the updated model.