@Uncle Robin: When the next KOReader stable is tagged (currently planned for November 12th, but don't hold us to that ;p), it'll hit the OCP.
The new devices dropped at a slightly awkward moment, and that meant that I wasn't completely happy with simply shipping a nightly in the OCP, like I did for the Elipsa (i.e., I'm still fixing weird Sage bugs ;p).
In the meantime, a manual install from a nightly works just fine, but you're probably better off waiting a few days if you're not comfortable with that

.
(Or if you're desperate, PM me/ping me on discord and I'll send you a nightly OCP

).