I've been wondering the same thing and have been seeking the answers. There's so much conflicting information on their website and online. I did hear back from Husqvarna and was told for 2019 both have the Kohler engine, the "D" has the tuff torq / locking diff, larger tires, and armrests. The 2019 XD has been changed apparently from 2018 and now has the fast hydrostatic (Hydro Gear) and apparently no arm rest(????) althougth that's not what the pic on their website shows. The gauges and led lights remain but it sounds like it may have smaller tires too???
I still can't get 100% confirmation the XD has the locking diff and the arm rests ... Really frustrating.
I still can't get 100% confirmation the XD has the locking diff and the arm rests ... Really frustrating.