Enable Plasma 6

Here is a short guide on how to switch from Plasma 5 to Plasma 6:

(You can always rollback to your old configuration)

First, run:

sudo nix-channel --add https://nixos.org/channels/nixos-unstable nixos

Now, the output of sudo nix-channel --list should look like this:

In case you have other channels, because you added some prior, it might look like that:

In that case, remove all channels other than the first, called nixos.
Delete the unstable channel in the example via:

sudo nix-channel --remove unstable


Edit the configuration file:
kwrite admin:///etc/nixos/configuration.nix

If you have any unstable.packagename in your configuration, remove the unstable part.
It gets in your way at build time. :slight_smile:

Kate is preinstalled now (hurrayy :tada:) and also stuff like kio-extras is now included implicitly.
So remove them entirely, if you have them defined.

Set all KDE packages to the new prefix kdePackages.
Example: kdePackages.kdenlive

If there is no version with this prefix available, you can use one without it.

Another group of packages that can cause some issues is the libsForQt5 group.
If these packages are now available with the kdePackages prefix, apply that one.


Finally, change
services.xserver.desktopManager.plasma5.enable = true; into
services.desktopManager.plasma6.enable = true;

Now run an update:

sudo nix-channel --update

And then finally build:

sudo nixos-rebuild switch

After restarting your machine, you should be in Plasma 6.

In case you boot into a black screen, add the following option, and rebuild:

services.xserver.displayManager.sddm.wayland.enable = true;

Comment for each issue, you encounter. :sun_with_face:


Thank you for this article! Everything is fine!
Can you please edit this line for displayManager =)

Thanks a lot, got it! :smile_cat:

will plasma 6 be available in stable before 24.05 or will be waiting for that? Happy to wait if so

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It will not be available in 23.11 to my knowledge.
The rollback is possible with no problem.

So you can simply try it, and if any issues occur, you go back.
Please report about your experience :slightly_smiling_face:

The problem I am facing after installing Plasma6 is that the apps aren’t being added to the app menu (they can still be ran if I type the package name)

UPDATE: The app menu now shows all the installed app after I set my default email app to Thunderbird

UPDATE: After experimenting a bit, I am able to force refresh by right-clicking the app menu icon > Edit Applications. Click edit then “Restore to system menu” and then CTRL+S and CTRL+Q (didn’t fix it at all)

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Just make an update. kcmutils was missing

it’s less enabling Plasma6 instead changing channel to unstable, incl.

  • changing prefixes
  • changing options
  • deleting old options
  • broken packages
  • issues like Fontconfig
    (- even sddm seems currently broken …)

How can you “roll back” (without to change everything back in your config to make other changes again)?

Even so specialisation are nice but they seem to only work within one channel?

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I am simply able to go back to the last generation that uses Plasma 5.

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This guide worked out for me on a fresh NixOS install. I was also able to rollback to the previous 23.11 with plasma 5 via the saved generations in the boot entry.

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qtspeech is now installed as a dependency of kcmutils. I didn’t find an option to override plasma6 to remove qtspeech.

Do you know how to remove it?

I recommend you to open a bug report on Github. :slightly_smiling_face:
qtspeech might simply be a dependency now, and the devs know best.

Can I also just use the necessary modules from unstable and keep the rest of my system on stable?

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No, not really.

Unstable is, unlike its name suggests, very stable :+1:

You can use it productive, and quite a couple people do so.

found this nixos option environment.plasma6.excludePackages

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But do you know about 24.05?

it will be very very likely in 24.05, as the branch-off will happen from master, and its in there, so it should be in 24.05 then.

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The last info that I got from the maintainer, was it it might not make the cut, at least not on the initial ISO. They are working on it :slightly_smiling_face:

I don’t think this would work with flakes unless you change nixpkgs.url to use unstable.

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