Upgrading Packages

Running apt upgrade does not upgrade the operating system (OS) version. Instead, it upgrades all the installed packages to their latest versions available within the current OS release. This includes security updates, bug fixes, and minor version upgrades for software packages managed by apt, the package management system used by Debian, Ubuntu, and other Debian-based Linux distributions.

What Does apt upgrade Do

  • Updates Package Lists: First, apt update should be run to refresh the local package index with the latest available software information from configured repositories.
  • Upgrades Installed Packages: Then, apt upgrade downloads and applies updates to all installed packages without removing packages or installing new ones that aren’t already installed.

Upgrading the OS Version

  • To upgrade the entire OS version to a new release (for example, from Ubuntu 20.04 LTS to Ubuntu 22.04 LTS), you would use a different command: do-release-upgrade on Ubuntu systems.
  • The process is more involved and includes updating sources to point to the new release’s repositories, upgrading all packages, and often requires manual intervention for configuration decisions.

Important Considerations

  • Stability and Compatibility: Regularly running apt upgrade is recommended for security and stability, but it’s essential to test updates in a controlled environment before applying them to production systems to ensure compatibility.
  • Kernel Updates: While apt upgrade can update the Linux kernel if a newer version is available in the repository for the current OS version, it doesn’t upgrade to a new major kernel version that would come with a new OS release.
  • Automatic Security Updates: For critical security patches, Debian-based systems can be configured to automatically apply security updates using the unattended-upgrades package.

In summary, apt upgrade is crucial for maintaining the security and performance of your Linux system by keeping software up to date within the scope of the current OS version, but it does not upgrade the OS to a new release.