Fresh KDE Neon installation on December 25th 2025 - error when updating

[Cosmin_KDE]

hi all!

And Merry Christmas to all!

Now, onto the point:

i have a fresh KDE Neon, Plasma 6 with Wayland installation - in fact, i installed it yesterday!

2 problems bug me:

Problem 1) When opening Discovery to update system (yes, yes, i know i can do it from cmd line..stick with me…), i get this ugly error thing:

E: The repository ‘noble Release’ does not have a Release file.
W: Updating from such a repository can’t be done securely, and is therefore disabled by default.
W: See apt-secure(8) manpage for repository creation and user configuration details.

Please, step by step…how do i fix this ?!

i know i must edit that sources.list…but how ?!

Is this a distro bug ? if so …how did it make it to release ?!?

Problem 2) I like the Oxygen theme instead of Breeze - but the global Oxygen theme is severely bugged !

In order for it to work properly, one must DISABLE two options in the theme settings (the ones in the screenshot): “Application Style” and “Plasma Style”

The Problem is made worse, because on reboot, these options self-re-enable ! /angry

What happens then, is that the background for start menu + a lot of other menus look weird, glitched - either no icons, just flat dark writing on flat black backgrounds etc !

Any ways to make that setting stick so Oxygen doesnt re-enable all options by itself… ?!?

As a last questions (mostly to myself) - how did these glaring issues made it into the final release distro ?! /shrug

Otherwise, KDE Neon looks and behaves lovely!

• OPTIONAL - Problem 3) Most key, important software in the official app store - Discover - is waaaayyyy out of date ! Not just a bit mind you, but by maaany months!

Fortunately, i know how to install from .debs, and cmd line…but still…it shouldnt be this way!

Linux Mint’s own app store, although also lagging behind, is only slightly behind current versions!

Thanks alot!

[claydoh]

Are you using the most current iso image, dated for 25 December? There is no ‘final’ release, and images are usually updated weekly or thereabouts.

It looks like a typo in your sources, as it should be just ‘noble’ and not ’ noble release’ in this sort of error, so I think there was a glitch or other error in some scripting somewhere.

Now, earlier this week, the repo server was down for a while. This isnt the problem now. It would have given you the same type of error about a missing ‘release’ file.

Look at your /etc/apt/sources.list.d/neon.sources and make sure that it looks like this:

Apologies for the image, I’m traveling and on mobile, and copying from the terminal while ssh-ing to my PC is not working on my phone. I’ll edit when I get the chance.

[Cosmin_KDE]

Hello!

Many thanks for the quick reply!

I dont have a text file named neon.sources anywhere!

Neither in that folder, /etc/apt/sources.list.d …nor in /etc/apt !

I didnt change anything!

My only files in /etc/apt are:

/etc / apt / sources.list
/etc / apt / sources.list.d / neon.list

So, i only have the text files named sources.list and neon.list…thats it!

I have no file named neon.sources anywhere in /etc/apt !

But i will put your text from your screeenshot into my text files, see if it works …

Btw, your screen shot looks good! Dont worry

And as far as Oxygen global theme…any ideas or suggestions ?

Many thanks again

[Cosmin_KDE]

Here are the contents of my neon.list

[Cosmin_KDE]

Here are the contents of my sources.list text file (in /etc/apt/)

[jivask]

My neon.list is identical to yours except the last line - I do not have it.

Oxygen theme is quite historical and although still available, it could be not compatible in all aspects of current plasma 6.5 desktop.

Old packages are the result of KDE Neon basing on Ubuntu 24.04 long term support version. So only KDE packages are up-to-date and the others (except Firefox) are still the versions Ubuntu manages. You can still use Ubuntu 24.04 community managed PPA-s for fresh Thunderbird, Libreoffice, Stellarium etc…

[Cosmin_KDE]

Hi and thanks for your reply.

i replicated what you have in neon.list (deleting the 3rd file).

Sadly…error persists …

What would you recommend i do in this scenario …?

Thank you

[claydoh]

@Cosmin_KDE

Btw, your screen shot looks good! Dont worry

Yes, I worry because I dislike using images in place of text, as it is very hard to copy-pasta, either for search purposes, or for providing correct, precise commands and the like. If I could type properly on my phone in a moving vehicle, and hadn’t cheaped out on the smaller screen option, I’d probably be OK lol

Ok, the PPA you added is truly ancient and does not have packages for Ubuntu 24.04.

You will need to delete the appropriate file for it from /etc/apt/sources.list.d. However, this error shouldn’t normally block updating or installing other software, at least it won’t from the command line.

Hopefully this solves Problem 1.
(Apologies for not seeking this information sooner. I ass-umed that “clean install” meant “no system changes from stock yet”, and I really do know better. )

However, you really should have a neon.sources file, as well as a neon.list that simply mentions that neon.sources is being used. While having the ‘old’ style source file won’t break things at all, it does point to a possible crashed installer or otherwise busted install, maybe? The live OS image does use the old neon.list file, but the installed OS should have both files as described above.

Problem 2, I have no idea. I haven’t really used Oxygen in over a decade, since back in the KDE 4 days. It is working for me here with no issues as you describe or any others.

Eew:

Problem 3: Can you give examples? Neon IS using Ubuntu LTS (aka Noble 24.04), so it’s overall software library will not be current, outside of Plasma and KDE related items. Use flatpak or snaps if you need the ultra current. If your KDE bits are older, that would be from using an older ISO image, though the current one does have Plasma 6.5.3, which will update to 6.5.4, so that would be slightly behind the current. if you can update properly now, that will solve that one, and maybe #2, maybe?

[Cosmin_KDE]

Hi and thanks for the reply!

Sadly, same error persists even when using command lines!

Look, my distro was a vanilla install - simply downloaded the image from KDE Neon site and installed it - thats it !

So the problems stem from the distro itself!
(Mageia has similar issues …)

Why dont distros like Mint or Ubuntu have same issues… ?!
They upgrade and work perfectly out of the box ….

**Now, with that said, yes i should have a neon.sources…but there is no such file on my system, just like i allready pointed out before !

So ,**…how do i solve it ?
Do i add a neon,sources? if so…with that content ?

What file do i need to delete / edit///? please tell me precisely !

@claydoh

However, this error shouldn’t normally block updating or installing other software, at least it won’t from the command line.

…but it does!

Thanks a lot!

[Cosmin_KDE]

Error in my cmd line as well !

[Cosmin_KDE]

yes …same error with update/ upgrade commands

[Cosmin_KDE]

So..for the record, to make things clear:

Contents of my /etc/ apt / sources.list:

deb http://archive.ubuntu.com/ubuntu/ noble main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu/ noble-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ noble-updates main restricted universe multiverse

=====================================================

Contents of my /etc / apt / sources.list.d / neon.list:

deb [signed-by=/etc/apt/keyrings/neon-archive-keyring.asc] http://archive.neon.kde.org/user noble main
deb-src [signed-by=/etc/apt/keyrings/neon-archive-keyring.asc] http://archive.neon.kde.org/user noble main
deb https://archive.neon.kde.org/user

My system does NOT contain a neon.sources text file !

Maybe it should…but it never has!

NOTE: in front of //, is http:
…but it keeps auto-replacing it with a named link!
how do i stop auto-formatting links in here ?!?!

[claydoh]

As I mentioned previously, you need to remove the sources file for that notepadqq PPA that hasn’t seen an update since 2018. This is what is causing the error message. This PPA does not have a Noble (24.04) repo, so there isn’t a ‘release’ file for it that apt is looking for and then complaining about. This third-party repo is a system type of modification, so things are no longer ‘vanilla’.

Having the old style *.list file format instead of the *.sources shouldn’t be a problem. Remove the PPA’s file (notepadqq-team-ubuntu-notepadqq-noble.sources), or try un-checking it in Discover’s settings section. This will get rid of the error message in Discover and apt. But still, this error isn’t blocking any updates. You just don’t have any at the moment.

If you want, you can replace the neon.list with a neon.sources that has the content I showed previously:

X-Repolib-Name: KDE neon noble user
Types: deb
URIs: http://archive.neon.kde.org/user/
Suites: noble
Components: main
Signed-By: /etc/apt/keyrings/neon-archive-keyring.asc

X-Repolib-Name: KDE neon noble user
Types: deb-src
URIs: http://archive.neon.kde.org/user/
Suites: noble
Components: main
Signed-By: /etc/apt/keyrings/neon-archive-keyring.asc
Enabled: yes

If you do want to update on the commandline, use apt. It gives more complete error messaging, for one, and pkcon is just an extra layer on top of it that doesn’t add or do anything special or extra.

So, after removing whatever file that old PPA created in /etc/apt/sources.list.d/, try updating with either your original neon.list or the new neon.sources.

[YamiYukiSenpai]

The issue is not tied to KDE Neon at all.

The Notepadqq PPA doesn’t support Noble (24.04).

If you need it, and you probably don’t because there’s Kate, download the Snap as suggsted.

the rep file for notepadqq would be in /etc/apt/sources.list.d. just delete that repo file.
You can ls -l /etc/apt/sources.list.d to see the contents of that directory.

[Cosmin_KDE]

YAAAY !

IT worked !

1. remove completely that notepad file that was in sources.d folder
2. remove completely the old neon.list
3. created a simple new text file neon.sources with your contents

Many thanks!

[Cosmin_KDE]

Thanks alot!

Indeed, this was the issue!

Pffft… :))

i deleted its file from that /etc/sources.d folder…thanks again!

Now…who can work wonders and make Global Oxygen Theme compatible with Plasma 6.5 ?

[HinzundKunz]

@Cosmin_KDE

Now…who can work wonders and make Global Oxygen Theme compatible with Plasma 6.5 ?

Two easy ways that are quite safe:

1. get used to Breeze. If you’re not totally fixed on a specific asthetic appearance, that should work. Icons are for guiding you visually, visual appeal is a secondary thing.

2. Find another icon set that you like that has Plasma 6.5 support and is visually similar to oxygen. There are quite a number out there (although I couldn’t care less, for the above reason. But I’m artistically challenged and don’t really care about visuals that much).

Then there’s a third, much harder way:
Download the oxygen theme and learn how to make it compatible. If you’re not into such things, don’t do it. It takes ages longer than you think, you make tons of errors and get frustrated on the way. I tried stuff like that a couple of times and always gave up after about ten hours of useless effort.