Upgrading from Debian 12 (Bookworm) to Debian 13 (Trixie)

Debian 13 "Trixie" has been available as the stable release since August 9, 2025, with the first point release 13.1 on September 6, 2025. The new version brings important improvements in security, performance, and package support.

Preparation: what you need beforehand

A smooth upgrade starts with a few checks to avoid downtime.

1. Backup: Create a full server backup via our web interface – quick and easy.

2. Update the system: Bring Debian 12 fully up to date.

   sudo apt update
   sudo apt full-upgrade -y
   sudo systemctl --failed

3. Resolve held packages: Holds can block the upgrade.

   apt-mark showhold
   sudo apt-mark unhold <package-name>  # if needed

4. Pause third-party sources: Comment out third-party repos (e.g. Docker, MariaDB).

   ls -1 /etc/apt/sources.list /etc/apt/sources.list.d/* 2>/dev/null
   grep -Rhs "deb " /etc/apt/sources.list{,.d/*} | nl

5. Console access: Make sure you have SSH access secured (e.g. via IPMI). Use screen for stability.

Tip: Plan a maintenance window – a reboot is required.

Step by step: how to upgrade

Follow these steps to move safely to Trixie.

1. Adjust APT sources: Replace "bookworm" with "trixie".

   sudo nano /etc/apt/sources.list

   Example content:

   deb http://deb.debian.org/debian/ trixie main non-free-firmware
   deb http://security.debian.org/debian-security trixie-security main non-free-firmware
   deb http://deb.debian.org/debian/ trixie-updates main non-free-firmware

   Alternatively (modern format):

   sudo nano /etc/apt/sources.list.d/debian.sources

   Content:

   Types: deb
   URIs: http://deb.debian.org/debian/
   Suites: trixie trixie-updates
   Components: main non-free-firmware
   
   Types: deb
   URIs: http://security.debian.org/debian-security
   Suites: trixie-security
   Components: main non-free-firmware

2. Package index and minimal upgrade:

   sudo apt update
   sudo apt upgrade --without-new-pkgs -y

3. Start the dist-upgrade:

   sudo apt full-upgrade -y

   Check configuration prompts (e.g. sshd_config) carefully.

4. Reboot and test:

   sudo reboot

   Afterwards:

   cat /etc/os-release
   uname -r
   systemctl --failed
   journalctl -p 3 -xb  # error logs

Follow-up: keeping your system stable

After the upgrade, secure the system's stability.

1. Remove leftovers:

   sudo apt autoremove --purge -y
   sudo dpkg -l | awk '/^rc/{print $2}' | xargs -r sudo apt purge -y

2. Check services:

   • Web server: PHP-FPM, modules, configurations.
   • Databases: MariaDB/PostgreSQL – upgrades needed?
   • Containers: Docker/Podman, networks.
   • Security: fail2ban, nftables, unattended-upgrades.

3. Reactivate third-party sources: Only Trixie-compatible repos, then:

   sudo apt update
   sudo apt full-upgrade -y

Note: Check the release notes for obsolete packages (e.g. fcitx4).

Pitfalls and solutions

• Third-party source conflicts: Disable them beforehand.
• Kept-back packages: Analyze with:

  sudo apt -o Debug::pkgProblemResolver=yes full-upgrade

• Boot problems: Regenerate GRUB/initramfs:

  sudo update-initramfs -u -k all
  sudo update-grub

• Obsolete packages: Check the list in the release notes.