Package: udev Version: 215-5+b1 Since version 215-5+b1 it is no longer possible to upgrade from Wheezy to Jessie with command
apt-get --download-only dist-upgrade because following error occurs: Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Failed The following packages have unmet dependencies: udev : Breaks: plymouth (< 0.9.0-7) but 0.8.5.1-5 is to be installed E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages. That problem didn't exist just few days ago when there was udev in version 208-8 in Jessie.