Update from 0.8 to 0.9 on Ubuntu/linux

I wonder how to update from 0.8 to 0.9 on Ubuntu 20.04

I checked Help>Check for updates> there is a new one, but nothing happens, no instalation.

Length: 52 [text/html]
Saving to: ‘././data//download.bin’
././data//download. 100%[===================>] 52 --.-KB/s in 0s

On gumroad there are to available files, but they do not work for me (I add belong the two response errors from terminal);


***:~/Applications/ArmorPaint_09dev_linux64/ArmorPaint$ ./ArmorPaint
Neither wayland nor X11 found.


***:~/Applications/ArmorPaintVKRT_09dev_linux64/ArmorPaintVKRT$ ./ArmorPaint
Segmentation fault (core dumped)

Thank you for help

I could run 0.9 compiling it with the github instructions.
But I would be nice to know how to update with the files in gumroad or from inside the application