Many Repositories are notoriously out of date. (as you found).
A few others ,'know better' and
adjust 
the code.
Calibre may not be optomized for a particular OS. It is a compromize, allowing it to run and APPEAR functionally the same over 3 major OS.
The standalone content server is not compatible with the GUI (Calibre). They can not be run together. You need to Stop the standalone content server to run the GUI. Why just not run the GUI Minimized?