http://lists.freedesktop.org/archives/systemd-devel/2014-May... (via http://redd.it/2a2tz5):
> Also note that at that point we intend to move udev onto kdbus as transport, and get rid of the userspace-to-userspace netlink-based tranport udev used so far. Unless the systemd-haters prepare another kdbus userspace until then this will effectively also mean that we will not support non-systemd systems with udev anymore starting at that point. Gentoo folks, this is your wakeup call.