i just bought a refurbished x220 to run on Steinberg only and indeed Halion 6. Combine it with voicemeeter in windows and this thing is going to be really fun. I also hope the Halion-installer will run on win 7 too because this thing is win 7. But when I look at the dorico part of the forum i expect it is going to work fine if you have the 4.6.2 .NET update in your win7, but ok, no official support.
kind regards,
R.