Both series use the IEEE-1901 standard, but the 5206 series transmits faster than the 4201 series. However, the speed is determined by the slower set, i.e. the 4201.

I have both the 4201 / 4201 v2 and the 5206 kit - with the result that it does not work! The two 4201s and the 5206 do not communicate with each other, there is some information on the internet about upgrading the firmware of the 4201, I will try that next. But just plugging it in and going for it definitely doesn't work!