How to Perform a Version Upgrade from Debian 11 to Debian 12

Debian, known for its stability and reliability, offers regular updates to keep the operating system secure and up-to-date. Upgrading from one major version to another is a common task to access the latest features and improvements. If you’re using Debian 11 (Bullseye) and want to make the transition to Debian 12 (Bookworm), this guide will walk you through the version upgrade process.

Before You Begin

Before you proceed with the version upgrade, there are some essential considerations:

1. Backup Your Data: It’s critical to back up your data and configuration files. While the upgrade process is generally smooth, unforeseen issues can occur.
2. Stable Internet Connection: Ensure you have a stable and reliable internet connection as the upgrade process involves downloading and installing a significant amount of data.
3. System Updates: Before starting the version upgrade, make sure your current Debian 11 system is fully up-to-date. Open a terminal and run the following commands:

   sudo apt update
   sudo apt upgrade

4. Read Release Notes: Familiarize yourself with the release notes for Debian 12 (Bookworm). They provide important information about changes and known issues in the new version.

Step 1: Update /etc/apt/sources.list

Debian uses the apt package manager for system updates and package installations. To upgrade to Debian 12, you’ll need to update the /etc/apt/sources.list file to point to the new Debian release. Open the file with a text editor:

sudo nano /etc/apt/sources.list

Inside the file, replace all occurrences of “bullseye” with “bookworm.” Make sure the file looks like this:

deb http://deb.debian.org/debian/ bookworm main contrib non-free
deb-src http://deb.debian.org/debian/ bookworm main contrib non-free

deb http://security.debian.org/debian-security bookworm/updates main contrib non-free
deb-src http://security.debian.org/debian-security bookworm/updates main contrib non-free

Save the file and exit the text editor.

Step 2: Update Package Information

Once you’ve modified the sources.list file, update the package information to reflect the changes:

sudo apt update

Step 3: Upgrade System Packages

Upgrade all installed packages to their latest versions:

sudo apt upgrade

This step ensures that your current Debian 11 system is prepared for the version upgrade.

Step 4: Initiate the Version Upgrade

Now, it’s time to initiate the actual version upgrade:

sudo apt dist-upgrade

The dist-upgrade command will install new packages, remove obsolete ones, and apply any necessary system changes to accommodate the new version.

Step 5: Cleaning Up

After the upgrade process completes, you should remove any residual or obsolete packages:

sudo apt autoremove

Step 6: Reboot Your System

Finally, reboot your system to apply all the changes and complete the version upgrade:

sudo reboot

Verification

Once your system has restarted, you can verify that the upgrade was successful by checking the Debian release:

lsb_release -a

You should see that your system is now running Debian 12 (Bookworm).

Conclusion

Congratulations! You’ve successfully performed a version upgrade from Debian 11 (Bullseye) to Debian 12 (Bookworm). Your system is now running the latest version of Debian, with access to its new features and improvements. Always remember to keep your system updated and maintain regular backups to ensure the stability and security of your Debian installation.