How to Upgrade Debian 10 Buster to Debian 11 Bullseye

How to Upgrade Debian 10 Buster to Debian 11 Bullseye

Recently, the newest Debian 11 version has been released in the market on 14 august 2021 with the name ‘Debian 11 Bullseye’ after working on two years of development. Most of the Linux users want to use this latest stable Debian version on your system. If you have already installed Debian 10 buster on your system then, you do not need to install a new one. You can easily upgrade the previous version to the new one after implementing some useful commands.

We will go through this tutorial on how you can upgrade your system from the previous Debian 10 buster to Debian 11 Bullseye version.


Create a backup of your system with all necessary files. This is for precautionary measures.

The upgrade process is quite straightforward. Login as root user on your Debian 10 buster system.

Steps to upgrade Debian 10 buster system to Debian 11 Bullseye

Follow the following steps to upgrade Debian 10 buster system to Debian 11 bullseye:

Step 1: Update and Upgrade system packages

First, make sure that all installed Debian 10 packages on your system are up to date. So, use the update command to update the packages index and then, upgrade packages to the latest version by executing the following command:

$ sudo apt update
$ sudo apt upgrade

Step 2: Display the currently installed Debian version

Print the installed Debian version on your system by using the below-given command on the terminal:

$ lsb_release -a

The following details about the installed system shows on the terminal:

Alternatively, one more command is also available to check the currently installed version which is mentioned below:

$ cat /etc/os-release

To view the only version number, type the following command:

$ cat /etc/debian_version

Step 3: Replace repositories of Debian 10 Buster with Debian 11 Bullseye

All Debian software repositories specified in ‘/etc/apt/sources.list’ file and located in ‘/etc/apt/sources.list.d/’ directory. So first, you need to reconfigure the Debian 11 Bullseye repositories on the current Debian 10 system. Access the content of the ‘/etc/apt/source.list’ file using any text editor. Here, we will use nano for our convenience.

$ sudo nano /etc/apt/sources.list

The following content shows in the file. Place the ‘#’ symbol before each line to comment on the previous configurations as follows:

It is your choice; you can also remove these lines instead of a comment.

Now, insert the following configuration lines at the end of this file.

deb bullseye main contrib non-free
deb bullseye-updates main contrib non-free
deb bullseye-security main
deb bullseye-backports main contrib non-free

Save the above configuration using ‘Ctrl+O’ and exit from the file using the shortcut ‘Ctrl+X’.

Step 4: Verify Debian 11 bullseye source list configurations 

Now, update the system repository to verify the addition of Debian 11 software repositories in your system.

$ sudo apt update

If no shows during the update process on the terminal window, it means the source list reconfigured successfully with Debian 11 Bullseye repositories.

Step 5: Upgrade system from Debian 10 to Debian 11 Bullseye

Finally, run the following system upgrade command to upgrade the system packages to the newest version.

$ sudo apt full-upgrade

The above process will take too much time to complete. So, make sure the system should remain awake or active during the above running process.

Few text wizards show on the screen, type ‘y’ and then hit ‘Enter’. In displaying wizards, the system will need to confirm permission to download and install the necessary packages.

Step 6: Reboot or restart the system

After completing the upgrade, use the following command to reboot your system:

$ sudo reboot

Step 7: Verify the installation of the Debian 11 bullseye version

Now, verify the installation of brand new Debian 11 Bullseye version by running the following command:

$ lsb_release -a


$ cat /etc/os-release

As you can see in the following window, Debian 11 Bullseye is now installed on this system:


We upgraded our system from Debian 10 Buster to Debian 11 Bullseye in this article. The Debian 11 Bullseye is the next stable Debian version but, still, it is in a testing stage. Therefore, you might face some problems after installing this version.

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