If you get a "Signature could not be verified" error when updating the repository, you likely need to re-import the developer's public GPG key. This usually happens when a repository changes its security certificates.
curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | sudo dd of=/usr/share/keyrings/githubcli-archive-keyring.gpg sudo chmod go+r /usr/share/keyrings/githubcli-archive-keyring.gpg echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" | sudo tee /etc/apt/sources.list.d/github-cli.list > /dev/null github for ubuntu upd