Raspbian bookworm upgrade

Upgrading your Raspberry Pi’s operating system can be a breeze, and with Raspbian Bookworm being the latest and greatest version available, it’s definitely worth considering. To start, make sure you have a stable internet connection and a compatible Raspberry Pi running Raspbian Bullseye. I will be upgrading my Raspberry Pi 3 that serves as my primary DNS server.

Before the upgrade

Before running any upgrade operations, make sure your Pi system is up to date. Run apt upgrades on the system:

apt update

apt full-upgrade

Also check what release you have installed, if you have installed Raspberry Pi OS recently you may already be on the newest release.

lsb_release -a

Upgrading

To upgrade your system, you need to edit the configured package repositories for the system to use the bookworm release instead of the previous release bullseye.

cd /etc/apt
sudo sed -i 's/bullseye/bookworm/g' sources.list
cat sources.list

After you run cat you should see the contents of the file, it should look like this:

deb http://raspbian.raspberrypi.org/raspbian/ bookworm main contrib non-free rpi
# Uncomment line below then 'apt-get update' to enable 'apt-get source'
#deb-src http://raspbian.raspberrypi.org/raspbian/ bookworm main contrib non-free rpi

There is likely another file in /etc/apt/sources.list.d/raspi.list. Update this file as well.

sudo sed -i 's/bullseye/bookworm/g' sources.list.d/raspi.list
cat sources.list.d/raspi.list

After you run cat you should see the contents of the file, it should look like this:

deb http://archive.raspberrypi.org/debian/ bookworm main
# Uncomment line below then 'apt-get update' to enable 'apt-get source'
#deb-src http://archive.raspberrypi.org/debian/ bookworm main

Now I recommend running the upgrade in a screen or tmux session in case your SSH connection is interrupted. These packages are most likely not installed on a default installation and can be installed as packages of the same name: apt install screen. To start a session just enter screen on the terminal and proceed with the rest of the commands. If your session is interrupted, the upgrade will continue and you can see the output and any prompts by typing screen -r.

Once you are ready in your screen or tmux session, enter the following to refresh the cache of packages and then run the upgrade.

apt update

apt dist-upgrade

There will likely be prompts that come up on the screen during the upgrade depending on your system.

Once the upgrade completes, reboot the server to reload all of the upgraded software.

reboot now

Next steps

Once the server has rebooted, the upgrade is complete. I had zero issues but even if you have a similar setup, I cannot guarantee you will not run into issues upgrading.