The DPT-RP1 line was acquired by Fujitsu and is now sold at the Quaderno. The hardware has been updated a bit in the Quaderno Gen 2, including a Wacom digitizer. They're still great devices, and the same open source software for the DPT-RP1 (dpt-rp1-py) works with both Quadernos.
You're linking to dpt-tools. I've never tried that software.
I have a Quaderno Gen 2 and personally use dpt-rp1-py (https://github.com/janten/dpt-rp1-py), so I can confirm that at least it works. (When I first set it up, I had to run the "dptrp1 register" command twice because I got an error message the first time, but that hasn't come up again -- you only have to register it once on a given computer.)
> You cannot sideload any apps, so you are stuck with the defaults, but the most damning thing, is that you cannot sideload PDF files, since the MooInk 2C lacks a PDF rendering engine.
You can see the price on this thing. Large e-ink screens are expensive, colour large e-ink screens even more so. How many people do you think would pay 900EUR+ for a device 2cm larger on each side?