When trying to plot anything within RKWard, there is an error:
Error in RK() : Graphics API version mismatch
(Just create a new skript-file with the following line:
and press “Run all”)
Workaround: Set Settings->ConfigureRKWard->OnscreenGraphics->PlatformDefaultDevice
Since this error has been already mentioned here
( https ://bugs.kde.org/show_bug.cgi?id=379232 ),
most probably RKWard needs to be re-built against the current version of R.