How to Upgrade Debian 12 to Debian 13 Trixie (2026 guide)
How to upgrade Debian 12 to Debian 13 Trixie without breaking production.
Debian 13 "Trixie" is now the stable release. This is the step-by-step method we use at SIXE to upgrade production servers: preparation, repositories, full-upgrade and a tested rollback plan. No surprises.
To upgrade from Debian 12 Bookworm to Debian 13 Trixie: back up, fully patch Bookworm, point the repositories from bookworm to trixie, run apt upgrade --without-new-pkgs first and then apt full-upgrade, clean up and reboot.
Simple on a lab box. A different story across a production fleet with databases, critical services and SLAs. At SIXE we have spent more than 15 years keeping Linux infrastructure running in production, and this is the exact methodology we use to run a dist-upgrade without unplanned downtime. Only the 12 → 13 jump is supported: if you are on Debian 11, move to Debian 12 first.
(3 yrs + 2 LTS)
the repositories
duration
What is Debian 13 Trixie and what changed from Bookworm?
Debian 13 "Trixie" has been the stable release of Debian since 9 August 2025. It ships the Linux 6.12 LTS kernel, the completion of the /usr merge (now mandatory), the move to 64-bit time_t (preparing the Year 2038 problem on 32-bit architectures) and APT 3.0, with cleaner output and better dependency resolution.
For a production server it is not a revolution but exactly what you expect from Debian: a cleaner base, a modern kernel and five years of security support ahead. The key operational point is that the support clock resets — and Bookworm's clock is starting to run out.
Trixie does not force you to relearn anything: same APT, same philosophy. The effort is in planning the jump, not adapting to a new system.
How long is Debian 12 Bookworm supported?
Since Trixie was released in August 2025, Debian 12 became oldstable. It keeps LTS security support until roughly June 2028, but it no longer receives full support from the security team. It is not a critical emergency, but every month you wait adds technical debt and shrinks the window to upgrade calmly.
Do not wait until the end of Bookworm's cycle. Plan the upgrade in a quiet window, not against the clock when security patches stop arriving.
What should you prepare before upgrading?
A dist-upgrade is safe if you prepare it. Most disasters we have seen come not from the upgrade itself but from skipping this phase. Tick every item before you start:
/ and /var to download the new packages./boot of old kernels so the 6.12 kernel fits.All six ticked? Then yes, go ahead with the upgrade.
How to upgrade Debian 12 to Debian 13 step by step
The process has six phases: bring Bookworm up to date, point repositories to trixie, disable third-party repos, run the minimal upgrade first and then the full one, clean up and reboot with verification. Here is the flow and the exact commands.
1. Bring Debian 12 fully up to date
Any pending patch turns into a conflict during the jump. Start from a pristine Bookworm:
$ sudo apt update $ sudo apt upgrade $ sudo apt full-upgrade $ sudo apt --purge autoremove
2. Point the repositories to Trixie
Replace bookworm with trixie in your APT sources. This also covers bookworm-security → trixie-security. Review the result with cat before continuing.
# Classic format $ sudo sed -i 's/bookworm/trixie/g' /etc/apt/sources.list # DEB822 format (recent Debian 12 installs) $ sudo sed -i 's/bookworm/trixie/g' /etc/apt/sources.list.d/debian.sources
3. Temporarily disable third-party repositories
Any external repo in /etc/apt/sources.list.d/ (Docker, PostgreSQL, etc.) can block the upgrade if it does not support Trixie yet. Disable them now and re-enable them one by one afterwards, checking that each already publishes for Debian 13.
4. Run the upgrade: minimal first, full second
The minimal upgrade reduces the risk of dependency conflicts. Monitor the process: you will answer a few prompts about modified configuration files.
$ sudo apt update $ sudo apt upgrade --without-new-pkgs # minimal upgrade $ sudo apt full-upgrade # full upgrade
5. Clean up obsolete packages
$ sudo apt --purge autoremove -y $ sudo apt autoclean
6. Reboot and verify
$ sudo reboot # after reboot: $ cat /etc/debian_version # -> 13.x $ uname -r # -> 6.12.x $ systemctl --failed # no failed services
How long does it take and can you roll back?
On a typical server the upgrade takes 20 to 60 minutes depending on the number of packages and disk and network speed. Rolling back a dist-upgrade is not trivial once the packages are installed: that is why the prior snapshot is non-negotiable. On VMs, reverting to the snapshot takes minutes; on physical hardware, the rollback plan is restoring from backup.
Never do a major version jump in production without a tested way back. A backup you have never restored is not a backup: it is a hope.
What are the most common errors upgrading to Trixie?
What we see most in production, and how to avoid it:
- Third-party repos without a Trixie release blocking
apt: disable them first (step 3). - Full
/bootpreventing the new kernel from installing: clean old kernels before you start. - Configuration files overwritten by accepting the package version blindly: when in doubt, keep yours and review afterwards.
- Forgetting
--without-new-pkgsin the minimal phase, which triggers dependency conflicts. - Custom services assuming non-merged
/usrpaths: the/usrmerge is now mandatory in Trixie.
Debian or Ubuntu for your server?
The question we get most often. There is no universal answer: it depends on whether you value control and independence (Debian) or integrated commercial support and tools like Ubuntu Pro and Landscape (Ubuntu). Here is the quick comparison:
Running Ubuntu? As a Canonical partner we have you covered too with SIXE UP. And if your case is moving between distributions, we handle migrations with no downtime.
What if you'd rather not touch production yourself?
Upgrading a lab box is an afternoon. Upgrading a production fleet with SLAs, databases and critical services is another story: you have to inventory dependencies, validate in staging, coordinate windows and have a tested rollback.
That is exactly what we do at SIXE. We offer professional Debian support — planned version upgrades, hardening with Wazuh monitoring, and incident resolution with SLA — and, when it is urgent, 24/7 support. Want your team trained? We run official Linux training.
Senior engineers who speak your language, no helpdesks, no escalations. Need to upgrade several servers to Debian 13? Tell us about your case and we will propose a plan with a maintenance window and rollback.
The essentials in 5 points
→ Debian 13 Trixie is the stable release since August 2025; Debian 12 is now oldstable (LTS until ~2028).
→ Back up / snapshot before anything else. It is your only real rollback.
→ Start from a 100% patched Bookworm, switch repos to trixie and run upgrade --without-new-pkgs before the full-upgrade.
→ Disable third-party repos during the process.
→ Only 12 → 13 is supported: from Debian 11, go through Debian 12 first.
Frequently asked questions
Can you upgrade from Debian 11 directly to Debian 13?
No. Debian only supports upgrades between consecutive releases. From Debian 11 "Bullseye" you must first upgrade to Debian 12 "Bookworm" and, once there, to Debian 13 "Trixie".
Do I lose my data and configuration when upgrading?
No, a dist-upgrade preserves data and configuration. Even so, a full backup or snapshot is mandatory: it is your rollback plan if anything fails.
Is it better to upgrade or reinstall from scratch?
For a well-maintained server, the dist-upgrade is safe and much faster. A clean reinstall only pays off if the system carries a lot of technical debt or inconsistent configuration.
References
Debian. Debian 13 "trixie" Release Information. debian.org/releases/trixie
Debian. Debian 13 Release Notes. debian.org/releases/trixie/releasenotes
Debian. Debian 13 "trixie" released (2025-08-09). debian.org/News/2025
Debian Security Team. debian.org/security
Written by the SIXE systems engineering team. Last updated: .
Need to upgrade your servers to Debian 13?
We propose an upgrade plan with a prior audit, staging validation, a maintenance window and a tested rollback. Senior engineering, with SLA.
