nvidia-installer, nvidia-settings, nvidia-xconfig are still at 280.04, there is no 280.11 release.
I checked both urls:
please update source packages of these apps to 280.11.
Please remove from all new driver package releases old headers:
glext.h glxext.h glx.h gl.h
they are very old - mesa provides new. gl.h is really bad because it is for M$ Windows not Linux - I do not know what it does here.