Zorin 17 → 18 Upgrade: APT sources not updated to Noble + Premium repo key issue

indru · February 26, 2026, 11:35am

Hi everyone,

I recently upgraded from Zorin OS 17 Pro to Zorin OS 18 Pro. The upgrade itself appeared to complete successfully — cat /etc/os-release confirms I'm running Zorin OS 18 with UBUNTU_CODENAME=noble. However, I've discovered two significant issues.

Issue 1: APT sources still pointing to Jammy after upgrade

After the upgrade, all of my APT sources — including the core Ubuntu repos and Zorin repos — were still pointing to jammy (Ubuntu 22.04) instead of noble (Ubuntu 24.04).

This includes:

/etc/apt/sources.list — all entries referenced jammy
/etc/apt/sources.list.d/zorin.list — all Zorin repos referenced jammy
/etc/apt/sources.list.d/zorinos-ubuntu-*.list — same issue

I had to manually run sed -i 's/jammy/noble/g' on these files to fix them. This seems like something the upgrade process should have handled automatically.

My question: Is this a known issue with the Zorin 17 → 18 upgrade, or did something go wrong on my end? Should I be concerned about package inconsistencies from having run a Noble-based system against Jammy repos for a period of time? Is there an official way to verify that the upgrade completed correctly?

Issue 2: Zorin Premium repo GPG key not valid for Noble

After updating the repos to noble, the premium repository fails signature verification:

W: GPG error: https://packages.zorinos.com/premium noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 55E9312A15BE5896
E: The repository 'https://packages.zorinos.com/premium noble InRelease' is not signed.

It appears the GPG key for the premium repo either changed with Zorin 18 or wasn't updated during the upgrade. I have a valid Zorin Pro license.

My question: What is the correct way to import the new GPG key for the Zorin 18 premium repository?

System info

OS: Zorin OS 18 Pro (upgraded from Zorin 17 Pro, previously upgraded from Zorin 16 Pro)
Base: Ubuntu 24.04 (Noble)
Architecture: amd64

Any help would be appreciated. Thanks!

wesoliv429 · February 26, 2026, 12:29pm

OK if i understand you upgraded to OS 18 from OS 17 pro.. my question is did you purchase the 18 Pro version or only the 17 pro?

indru · February 26, 2026, 12:48pm

I purchased the 18 Pro, I have an 18 PRO key from support.

wesoliv429 · February 26, 2026, 1:25pm

ok awsome and thanks for supporting the community.. see if in the zorin os updater if pro is visible. if so click it and enter the email address you used for the purchase and the support code then next/continue it shoud ask if ya want full install or minimal install choose one then next/continue and it should upgrade the install to pro version.. if not you may have to contact support

indru · February 26, 2026, 2:13pm

It is already the PRO version, this is how I installed it. By upgrading via the Upgrader from Zorin 17.3 Pro to Zorin 18 Pro. There is nothing left to do in the upgrader anymore.

Ponce-De-Leon · February 26, 2026, 2:35pm

Did You had during the Upgrade any Issues or Erros? Could You post the Output of the Command sudo apt update && sudo apt upgrade please? And show the Content of the sources.list File and the sources.list.d Folder please?

Aravisian · February 26, 2026, 9:44pm

The *.list.save files can safely be ignored when they say "focal" or "Jammy" instead of "noble."

Since you adjusted all the sources, I am not sure if we can confirm now, after the fact, which may have been irrelevant files.
And if a repository is harmless but does not have a "noble" release file, the orphaned "jammy" file can be left behind.

This, however, clearly stands out as an error - and I would recommend using the Pro Contact Form to submit this to the developers.

indru · March 6, 2026, 9:54pm

This was my original output, after I replaced the jammy string with noble, to try and adapt manually (this had already fixed some previous issues, reducing the errors):

indru@indru-Zorin-HQ:~$ sudo apt update
[sudo] password for indru:             
Ign:1 https://repo.pritunl.com/stable/apt noble InRelease
Err:2 https://repo.pritunl.com/stable/apt noble Release                                                                                                                                                                                      
  Cannot initiate the connection to repo.pritunl.com:443 (2606:4700:10::6814:21e4). - connect (101: Network is unreachable) Cannot initiate the connection to repo.pritunl.com:443 (104.20.33.228). - connect (101: Network is unreachable) Cannot initiate the connection to repo.pritunl.com:443 (2606:4700:10::ac42:9d79). - connect (101: Network is unreachable) Cannot initiate the connection to repo.pritunl.com:443 (172.66.157.121). - connect (101: Network is unreachable)
Ign:3 http://ppa.launchpad.net/zorinos/apps/ubuntu noble InRelease                                                                                                                                                                           
Ign:4 http://ppa.launchpad.net/zorinos/drivers/ubuntu noble InRelease                                                                                                                                                                        
Ign:5 http://ppa.launchpad.net/zorinos/patches/ubuntu noble InRelease                                                                                                                                                                        
Ign:6 http://ppa.launchpad.net/zorinos/stable/ubuntu noble InRelease                                                                                                                                                                         
Err:7 http://ppa.launchpad.net/zorinos/apps/ubuntu noble Release                                                                                                                                                                             
  Cannot initiate the connection to ppa.launchpad.net:80 (2620:2d:4000:1::81). - connect (101: Network is unreachable) Cannot initiate the connection to ppa.launchpad.net:80 (185.125.190.80). - connect (101: Network is unreachable)
Err:8 http://ppa.launchpad.net/zorinos/drivers/ubuntu noble Release                                                                                                                                                                          
  Cannot initiate the connection to ppa.launchpad.net:80 (2620:2d:4000:1::81). - connect (101: Network is unreachable) Cannot initiate the connection to ppa.launchpad.net:80 (185.125.190.80). - connect (101: Network is unreachable)
Err:9 http://ppa.launchpad.net/zorinos/patches/ubuntu noble Release                                                                                                                                                                          
  Cannot initiate the connection to ppa.launchpad.net:80 (2620:2d:4000:1::81). - connect (101: Network is unreachable) Cannot initiate the connection to ppa.launchpad.net:80 (185.125.190.80). - connect (101: Network is unreachable)
Err:10 http://ppa.launchpad.net/zorinos/stable/ubuntu noble Release                                                                                                                                                                          
  Cannot initiate the connection to ppa.launchpad.net:80 (2620:2d:4000:1::81). - connect (101: Network is unreachable) Cannot initiate the connection to ppa.launchpad.net:80 (185.125.190.80). - connect (101: Network is unreachable)
Hit:11 https://brave-browser-apt-release.s3.brave.com stable InRelease                                                                                                                                                                       
Hit:12 http://security.ubuntu.com/ubuntu noble-security InRelease                                                                                                                                                                            
Hit:13 http://archive.ubuntu.com/ubuntu noble InRelease                                                                                                                                                                                      
Hit:15 http://ro.archive.ubuntu.com/ubuntu noble-updates InRelease                                                                                                                                                                           
Hit:16 http://ro.archive.ubuntu.com/ubuntu noble-backports InRelease                                                                                                           
Hit:17 https://ppa.launchpadcontent.net/ubuntuhandbook1/annotator/ubuntu noble InRelease                                 
Hit:18 https://packages.microsoft.com/repos/edge stable InRelease                                                       
Hit:19 https://ppa.launchpadcontent.net/vcmi/ppa/ubuntu noble InRelease                                                 
Hit:14 https://packages.microsoft.com/repos/code stable InRelease                                                       
Hit:20 https://packages.mozilla.org/apt mozilla InRelease                                         
Hit:21 https://packages.zorinos.com/stable noble InRelease                  
Hit:22 https://packages.zorinos.com/patches noble InRelease
Hit:23 https://packages.zorinos.com/apps noble InRelease
Hit:24 https://packages.zorinos.com/drivers noble InRelease
Get:25 https://packages.zorinos.com/premium noble InRelease [15.5 kB]
Err:25 https://packages.zorinos.com/premium noble InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 55E9312A15BE5896
Reading package lists... Done
E: The repository 'https://repo.pritunl.com/stable/apt noble Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://ppa.launchpad.net/zorinos/apps/ubuntu noble Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://ppa.launchpad.net/zorinos/drivers/ubuntu noble Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://ppa.launchpad.net/zorinos/patches/ubuntu noble Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://ppa.launchpad.net/zorinos/stable/ubuntu noble Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: https://packages.zorinos.com/premium noble InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 55E9312A15BE5896
E: The repository 'https://packages.zorinos.com/premium noble InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I've then raised a ticket with the Zorin Team, but they said this:

That was not an option for me, since the very purpose of upgrading was to avoid a clean installation. And given Linux's modularity, it was impossible not to find a fix that didn't involve reinstalling.

And yes, I managed to find it.
In the end, I fixed it with the help of AI, without reinstalling.

Fixes (both in relation to Issue 2):

Missing https::User-Agent in /etc/apt/apt.conf.d/99zorin-os-premium-user-agent — bug in Zorin's package, was only setting it for HTTP. (This was very strange and it broke multiple repos, not just the Zorin one. I am honestly not sure the AI assertion of a bug is accurate, it might be some hiccup during the upgrade)

Manual fix for this:

sudo nano /etc/apt/apt.conf.d/99zorin-os-premium-user-agent

Change it to:

Acquire
{
    http::User-Agent "Zorin OS Premium";
    https::User-Agent "Zorin OS Premium";  //Basically I added this line, as it was missing.
};

Outdated GPG key — Zorin re-signed the premium repo with a new 2025 key but never shipped it via an updated zorin-os-premium-keyring package. The correct key was inside the ISO's squashfs. (Basically, the upgrade did not add the new keyring, I had to take it manually from the ISO that I had to also download separately. This sounds to me like a bug, based on the fact I still had jammy repos all over as well.)

Manual fix after mounting the ISO, if anybody else encounters this:

sudo mkdir -p /mnt/squashfs            
sudo mount -o loop "/media/indru/Zorin OS 18 Pro 64bit/casper/filesystem.squashfs" /mnt/squashfs  ##replace "indru" with your username and correct the path to point to the ISO mount

sudo cp /mnt/squashfs/etc/apt/trusted.gpg.d/zorin-os-premium.gpg /etc/apt/trusted.gpg.d/zorin-os-premium.gpg

##The last command was to revert the allow-insecure setting that I had previously issued during trial&error, you might not need it:
sudo sed -i 's|deb \[allow-insecure=yes\] https://packages.zorinos.com/premium|deb https://packages.zorinos.com/premium|' /etc/apt/sources.list.d/zorin.list

I've forwarded this information to the Zorin Team, as it seems like something they should be aware of.

Now, my output looks OK:

indru@indru-Zorin-HQ:/media/indru/Zorin OS 18 Pro 64bit$ sudo apt update
Hit:1 https://brave-browser-apt-release.s3.brave.com stable InRelease
Hit:2 http://ro.archive.ubuntu.com/ubuntu noble-updates InRelease                                                                                                                                                                            
Hit:3 http://ppa.launchpad.net/zorinos/apps/ubuntu noble InRelease                                                                                                                                                                           
Hit:4 http://security.ubuntu.com/ubuntu noble-security InRelease                                                                                                                                                                             
Hit:6 http://ro.archive.ubuntu.com/ubuntu noble-backports InRelease                                                                                                                                                                          
Hit:7 http://ppa.launchpad.net/zorinos/drivers/ubuntu noble InRelease                                                                                                                                                                        
Hit:8 http://archive.ubuntu.com/ubuntu noble InRelease                                                                                                                                                                       
Hit:9 http://ppa.launchpad.net/zorinos/patches/ubuntu noble InRelease                                                                                                                                  
Hit:10 http://ppa.launchpad.net/zorinos/stable/ubuntu noble InRelease                                                                                                        
Hit:11 https://packages.microsoft.com/repos/edge stable InRelease                                                                                                            
Hit:12 https://ppa.launchpadcontent.net/cdemu/ppa/ubuntu noble InRelease                                                                       
Hit:5 https://packages.microsoft.com/repos/code stable InRelease                                                         
Hit:13 https://repo.pritunl.com/stable/apt noble InRelease                                                               
Hit:14 https://ppa.launchpadcontent.net/ubuntuhandbook1/annotator/ubuntu noble InRelease                                 
Hit:15 https://ppa.launchpadcontent.net/vcmi/ppa/ubuntu noble InRelease                            
Hit:16 https://packages.mozilla.org/apt mozilla InRelease                    
Hit:17 https://packages.zorinos.com/stable noble InRelease                  
Hit:18 https://packages.zorinos.com/patches noble InRelease
Hit:19 https://packages.zorinos.com/apps noble InRelease
Hit:20 https://packages.zorinos.com/drivers noble InRelease
Get:21 https://packages.zorinos.com/premium noble InRelease [15.5 kB]
Fetched 15.5 kB in 3s (6,061 B/s)     
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
3 packages can be upgraded. Run 'apt list --upgradable' to see them.