kjs

Just updated many armbian files shown as available for update. After the update sudo apt update shows the error message: E: The repository 'http://apt.armbian.com bookworm Release' is no longer 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. How can I fix this or was signing simply forgotten? Thank you!