KDE's Plasma Login Manager (PLM) arrives February 17 in Plasma 6.6, replacing SDDM as the default login manager after over a decade. The architectural decision: hard dependencies on systemd-logind and systemd user services for session management, permissions, and seat handling.
This makes PLM unusable on FreeBSD, OpenBSD, and systemd-free Linux distributions like Devuan and Alpine. In December, KDE formally dropped FreeBSD support through a merge request. Arch Linux and CachyOS already ship with PLM as of January.
KDE developer David Edmundson explained the trade-off: maintaining code for non-logind systems required disproportionate effort for the small team. Modern Linux desktop development increasingly standardizes on systemd's logind for unified session management.
What this means in practice: FreeBSD users can still run the Plasma desktop. They'll continue using SDDM, which remains systemd-independent, or switch to alternatives like LightDM. PLM is the default login manager for Plasma 6.6, not a requirement for the desktop environment itself.
Worth noting: This reflects broader industry consolidation. Upstream desktop projects increasingly optimize for systemd-based distributions. Organizations running heterogeneous Unix/Linux environments - common in APAC financial services and government - should expect higher maintenance burden for non-standard deployments.
The fine print matters here. SDDM isn't being deprecated. BSD support for Plasma continues. What changed is the default path forward, and where KDE invests development effort. Systemd-free distributions will likely fork SDDM or maintain their own login managers.
For CTOs evaluating Linux desktop strategies: the era of write-once-run-anywhere Unix portability continues its slow decline. Desktop Linux means systemd Linux for major upstream projects. Budget accordingly.