I could NOT make my Apple Watch work with
MDE for the life of me this last July... I tried contacting their support but they were unable to offer any suggestions at all aside from logging out and back in again and asking three times if I was using a supported model and OS (yes and yes). It did work OK though my phone, though I had to make sure the app was open and click on the link to unlock our door every time which was annoying. Hopefully they bring the ability to DL if they get it working reliably as wearing two things makes for even sillier tan lines.