Upgrade Debian 11 to Debian 12

The process of upgrading from Debian 11 to Debian 12 is fairly straightforward for those that have been doing it for a while, but for those that are not familiar, it can be a daunting task. In this article, I’ll present two different options for upgrading: Manual and Automated. The automated (scripted) process is the same as the manual process, so please work the manual process in your environment before using the script. As always, please be sure you’ve got a proper backup of your machine before starting the process!

1: Update system

Before doing the upgrade, you must ensure your system is running the current latest packages within your current version.

sudo apt update && sudo apt upgrade && sudo apt full-upgrade

2: Make a backup of your current /etc/apt/sources.list file

In case anything goes wrong while updating the sources.list file, it’s always good to have a backup.

cp /etc/apt/sources.list /etc/apt/sources.list.orig

3: Modify /etc/apt/sources.list

You may choose your favorite text editor, but in this example, I’ll use nano for the process.

sudo nano /etc/apt/sources.list

4: Clean and update package lists

Make sure that aptitude has the right packages/versions, without any of the old “stuff”.

sudo apt clean

sudo apt update

5: Perform the upgrade

sudo apt upgrade

sudo apt full-upgrade

6: Remove old packages

This will remove the old/unrequired packages. Please be sure to review this list to ensure you don’t accidentally delete something you need.

sudo apt autoremove

Automated process:

If you’ve gotten this far, you probably already know what you’re doing and are just looking for a shortcut. I’ve created the following script to make things easier/quicker. I’ve tested this on my installations, but please verify that the sed commands will work in your environment before running them. In the event that there is a problem, the script makes a backup of your sources.list file, which you can restore.

curl https://code.flatironnetworks.com/RobFauls-Com/website-scripts/raw/branch/main/Linux/Debian/Upgrade/Upgrade-Debian11toDebian12.sh --output debian_upgrade.sh && sh debian_upgrade.sh