There is a whole lot to say about the stable GUI in Calibre.
'Right click the Globe Icon to start/shutdown the Content server'
How many versions, does that still hold true?
That makes support easy-peasy, as we have users on versions from 3-8 due to OS and HW limitations. Some icons have style changes but the
main element of it is still the same.
Folk that are comfortable with Calibre, also know how to apply a 'skin' (and what their versions icons mean.