LT for Mac is up to version 2016.
LT for Windows is up to version 2017.

The MAC is a vastly different look and feel, but IMHO if you bought a MAC why on earth would you hobble it with WIndows? isn't the whole point of you buying a Mac is to get away from Windows? WIndows doesn't become magical on MAC hardware, all the hardware is pretty much all the same these days.

You can probably still buy Win8.1 if WIn10 is not cutting it for you.