Debian 13 Trixie: Release Date, Kernel Version and How to Upgrade from Debian 12

Applies to: Debian 13 (trixie), point release 13.7; upgrade tested from Debian 12.15 to 13.7 in Docker (arm64)

Debian 13, codename “trixie”, was released on 9 August 2025. It ships the Linux 6.12 LTS kernel. Debian supports it fully until 9 August 2028, and Debian LTS extends security support until 30 June 2030. At the time of writing the latest point release is 13.7.

Key facts

• Kernel: 6.12 LTS series. Point releases update it; our arm64 test system offered linux-image-arm64 version 6.12.111-1.
• Architectures: amd64, arm64, armhf, ppc64el, riscv64, s390x and armel. riscv64 is official for the first time, and this is the last release for armel. i386 is no longer a regular architecture: there is no official kernel or installer for it.
• Debian 12 (bookworm): its regular security support ended on 11 June 2026. Debian LTS covers it until 30 June 2028, for fewer architectures, so plan the upgrade.

Package versions in Debian 13

What apt-cache policy offered on our 13.7 system (point releases can raise these):

apt              3.0.3
systemd          257.13
openssh-server   10.0p1
python3          3.13.5
php              8.4
perl             5.40.1
gcc              14.2.0
apache2          2.4.68
nginx            1.26.3
mariadb-server   11.8.6
postgresql       17
openssl          3.5.7
bash             5.2.37

Check which version you run

$ cat /etc/debian_version
13.7
$ grep -E '^(VERSION|VERSION_CODENAME)=' /etc/os-release
VERSION="13 (trixie)"
VERSION_CODENAME=trixie

Changes that matter on a server

From the Debian 13 release notes:

• /tmp is now in memory (tmpfs, up to 50% of RAM by default). On upgraded systems this starts after the reboot. Large files in /tmp now use RAM; to keep the old behaviour, run systemctl mask tmp.mount and reboot. A separate /tmp in /etc/fstab is not affected.
• /etc/sysctl.conf is no longer read. Move your settings to a file in /etc/sysctl.d/, for example /etc/sysctl.d/local.conf. See change kernel parameters with sysctl.
• OpenSSH no longer supports DSA keys. Replace any DSA key before you upgrade, or you lose that login.
• Network interface names can change on some hardware (the i40e network driver, or firmware that exposes the ACPI _SUN object). Without console access, the notes advise pinning the current name with a systemd .link file before the upgrade.
• ISC DHCP is deprecated. Systems using ifupdown should use dhcpcd-base instead.

Upgrade from Debian 12 to Debian 13

1. Prepare. Take a backup or snapshot, make sure you have console access (VNC or IPMI) in case the network doesn’t come back, and bring Debian 12 fully up to date: sudo apt update && sudo apt full-upgrade.
2. Look for packages that are not from Debian, as they are the most likely to break:

   apt list '?narrow(?installed, ?not(?origin(Debian)))'

3. Point APT at trixie. Find every mention of bookworm, then change the Debian entries:

   grep -rn bookworm /etc/apt/
   sudo sed -i 's/bookworm/trixie/g' /etc/apt/sources.list    # or /etc/apt/sources.list.d/debian.sources

   Check third-party repositories separately; only switch them when they offer a trixie version.
4. Check the disk space the upgrade needs: sudo apt -o APT::Get::Trivial-Only=true full-upgrade.
5. Upgrade in two steps, inside tmux or screen so a dropped SSH session doesn’t stop it:

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

   In our test the first step upgraded 104 packages; the second upgraded 40, installed 21 new ones and removed 7. Read each configuration file prompt: keeping your version is the safe choice if you changed that file.
6. Reboot into the new kernel and check the version. In our test (a container, so without the reboot) cat /etc/debian_version showed 13.7, Nginx went from 1.22.1 to 1.26.3 and APT from 2.6.1 to 3.0.3.
7. Clean up: sudo apt autoremove, then convert your sources to the new format with sudo apt modernize-sources. It asked Rewrite 1 sources? [Y/n], wrote /etc/apt/sources.list.d/debian.sources and kept the old file as /etc/apt/sources.list.bak.

More: update packages safely with apt and dnf, how systemd cleans /tmp and set up SSH keys to replace an old DSA key.

Official documentation: Debian 13 release information, upgrading from Debian 12 and issues to be aware of.