This article currently (2021) contains only instructions for updates that were required years ago, and should no longer be needed. If a more involved upgrade (that requires instructions) happens again, it should be accompanied by a corresponding news item (that should be read and followed), and may also get a new entry here.
The compatibility symlinks /bin/systemctl and /bin/systemd pointing to /usr/lib/systemd/systemd are deprecated. The ebuild checks whether the system was booted using compatibility symlinks and refuses to build the new version of systemd.
To upgrade systemd, update the bootloader to use init=/usr/lib/systemd/systemd and reboot the system.
See the udev upgrade article.
graphical.target now depends on the display-manager.service for starting a display manager like GDM, KDM, etc. . Create a new .service file, e.g. for KDM:
[Unit] Description=KDM Display Manager Conflictsfirstname.lastname@example.org After=systemd-user-sessions.service email@example.com plymouth-quit.service [Service] ExecStart=/usr/bin/kdm -nodaemon Restart=always IgnoreSIGPIPE=no [Install] Alias=display-manager.service
Now enable the new service, e.g. for KDM:
systemctl enable kdm.service
Afterwards starting KDM with systemd >=187 should work. Disable and delete the old .service file (e.g. kdm@.service).
For the rationale and more informations see the Fedora 18 feature "Display Manager Infrastructure Rework".