How to downgrade KDE Plasma versions?

Help
1

I have KDE enabled with services.desktopManager.plasma6.enable = true;, but what if I wanted to for example: downgrade from Plasma 6.5 to 6.4? In case I come across bugs or API breakage and want to wait for fixes.

2
  1. Add previous nixpkgs input in flake.nix
    nixpkgs-prev.url = "github:nixos/nixpkgs/<commithash>"; # replace the commithash
  1. write an overlay for kdePackages (put it in overlays/kde.nix)
{
  nixpkgs-prev,
  system,
  ...
}: final: prev: {
  kdePackages = nixpkgs-prev.legacyPackages.${system}.kdePackages;
}
  1. import this file in configuration.nix (or other config file in your dotfiles)
  nixpkgs.overlays = [
    (import ./overlays/kde.nix) # replace with the actual path
  ];

You could find commit hash at the commit history of the repository GitHub - NixOS/nixpkgs: Nix Packages collection & NixOS at GitHub

3

If you’re using NixOS with services.desktopManager.plasma6.enable = true;, Plasma versions are generally tied to the Nixpkgs channel you’re on. To downgrade from Plasma 6.5 to 6.4, the most reliable approach is to pin or switch to an older Nixpkgs revision where Plasma 6.4 is still packaged.

You can do this by:

  • Using a previous NixOS channel (e.g. an earlier stable release)

  • Pinning nixpkgs via flakes or niv

  • Rolling back to an older system generation if it was built with Plasma 6.4

This kind of version pinning is similar to how PrusaSlicer users lock specific releases to avoid regressions or breaking changes until fixes are available.

1 Like