The preinst code which guaranteed lockstep upgrades of udev and kernel packages does not work reliably anymore, apparently because apt now tries to install the kernel and udev packages with different dpkg runs. We need a new solution which does not require users to manually disable the check...
IIRC the output of "dpkg -l" indicates that a package is "about to be installed" in the first two characters of the corresponding line.
Hope this helps... - Fabian