KDE Ni! OS is a custom flavour(configuration, not a separate distribution) of NixOS that showcases KDE software. Itbuilds on NixOS with the aim to reimplement the same features otherpopular immutable distributions have, while providing a first-class KDEPlasma setup.The Plasma Login Manager support has been merged into Ni! OS.If you want to use it, there are two prerequisites:you are using Wayland, not X11; andyou are on unstable NixOS.It is in the “works for me” state. I don’t use auto-login,virtual keyboard, etc.Going unstableIf you are on the stable channel, which would surprise me asyou’re reading this post, it is easy to switch to unstable justby running these commands as root user (sudo,or su, or…).nix-channel --add https://channels.nixos.org/nixos-unstable nixosnix-channel --updatenixos-rebuild switch --upgrade This will switch you to the unstable version of NixOS.Mind that, as NixOS is an immutable distribution, you can easily bootback into the stable version – the previous version of your system isstill accessible in the bootloader menu.Switching fromSDDM to the Plasma Login ManagerThere’s a new option in Ni! OS called experimental.use_plasma_login_manager.The only thing you need to do in order to switch from SDDM to the PlasmaLogin Manager is to set it to true, and justswitch your setup to the new configuration with:nixos-rebuild switchPlasma Login Manager on Ni! OSSwitching back is also trivial – just change the value back tofalse and do the switch again.There and backOne new thing in Ni! OS is a custom label for the versions of thesystem (derivations in NixOS terminology).If you enable an experimental feature such as the Plasma LoginManager, the label will clearly denote that. It makes it easy to getback to a version without the experimental features enabled.As you can see in the following screenshot, the default label iskde-ni-os and all enabled experimental features areappended to it – when enabling the Plasma Login Manager, the labelbecomes kde-ni-os:plasma-login-manager. These labels can beseen in the following screenshot:Boot menu with labels shown