Unable to install on Ubuntu 26.04 LTS

[mattgroves]

Testing for Ubuntu 26.04 LTS released yesterday.

Following the Salt docs at https://docs.saltproject.io/salt/install-guide/en/latest/topics/install-by-operating-system/linux-deb.html for installing on a DEB based system fails initially with (this is via our custom server prep script):

The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 64CBBC8173D76B3F
Warning: https://packages.broadcom.com/artifactory/saltproject-deb/dists/stable/InRelease: The key(s) in the keyring /etc/apt/keyrings/salt-archive-keyring-2023.pgp are ignored as the file has an unsupported filetype.
Warning: OpenPGP signature verification failed: https://packages.broadcom.com/artifactory/saltproject-deb stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 64CBBC8173D76B3F
Error: The repository 'https://packages.broadcom.com/artifactory/saltproject-deb stable InRelease' is not signed.
Notice: Updating from such a repository can't be done securely, and is therefore disabled by default.
Notice: See apt-secure(8) manpage for repository creation and user configuration details.

and running the commands manually:

root@test-ubuntu-2604lts:~# # Ensure keyrings dir exists
mkdir -m 755 -p /etc/apt/keyrings
# Download public key
curl -fsSL https://packages.broadcom.com/artifactory/api/security/keypair/SaltProjectKey/public | gpg --dearmor | sudo tee /etc/apt/keyrings/salt-archive-keyring.pgp > /dev/null
# Create apt repo target configuration
curl -fsSL https://github.com/saltstack/salt-install-guide/releases/latest/download/salt.sources | sudo tee /etc/apt/sources.list.d/salt.sources
X-Repolib-Name: Salt Project
Description: Salt has many possible uses, including configuration management.
  Built on Python, Salt is an event-driven automation tool and framework to deploy,
  configure, and manage complex IT systems. Use Salt to automate common
  infrastructure administration tasks and ensure that all the components of your
  infrastructure are operating in a consistent desired state.
  - Website: https://saltproject.io
  - Public key: https://packages.broadcom.com/artifactory/api/security/keypair/SaltProjectKey/public
Enabled: yes
Types: deb
URIs: https://packages.broadcom.com/artifactory/saltproject-deb
Signed-By: /etc/apt/keyrings/salt-archive-keyring.pgp
Suites: stable
Components: main
root@test-ubuntu-2604lts:~# apt update
Error: Conflicting values set for option Signed-By regarding source https://packages.broadcom.com/artifactory/saltproject-deb/ stable: /etc/apt/keyrings/salt-archive-keyring-2023.pgp != /etc/apt/keyrings/salt-archive-keyring.pgp
Error: The list of sources could not be read.
root@test-ubuntu-2604lts:~# 

[mattgroves]

I realise this OS version is not yet supported so hopefully it will contribute towards getting it listed

[dafyddj]

I don't have any such problem - the Debian packages are not Distro/version specific.
You seem to already have some outdated keys on the system /etc/apt/keyrings/salt-archive-keyring-2023.pgp
so it seems you need to start with a blank slate or update your custom server prep script.