I'm a big fan of Decksaver. Yes, they're expensive, but they do the job nicely and look good while at it. Apparently the Subsequent37 is 5mm wider than the Sub37. Also the curve seems to have changed a bit, which makes the cover also a couple of mm too short. But that doesn't hinder the fit too much. The width does however.
I contemplated my options and decided to use a Dremel multitool to cut off one edge so that the keyboard would be covered at least. In the process I also cut off 20mm of the font bottom part. It was much longer than for example the covers I have for the Matriarch and Grandmother. The Subsequent37 is mounted on a Jaspers stand, and the modified Decksaver now fits snug and doesn't slide off.
All in all too bad that Decksaver failed on this one. Won't stop me from buying other covers for my gear. But I'll make sure to read the reviews properly first :)