How to install a package from Debian backports

Installing one package from Debian backports lets a stable Debian host use a newer build without changing the default package source for the whole system. This fits a reviewed tool, driver helper, or application that needs the version maintained for the matching stable-backports suite.

Backports packages are visible to APT after the matching suite is enabled, but they are pinned below normal stable packages. On Debian 13, trixie-backports packages normally appear at priority 100, while stable packages remain at priority 500 unless a package is selected from backports.

Use backports as an explicit opt-in for the package you reviewed. The official single-package form is package/trixie-backports; use -t trixie-backports only when required dependencies should also be selected from backports.

1. Refresh the APT package lists after enabling backports.

   $ sudo apt update
   Get:1 http://deb.debian.org/debian trixie-backports InRelease [54.0 kB]
   Hit:2 http://deb.debian.org/debian trixie InRelease
   Hit:3 http://deb.debian.org/debian trixie-updates InRelease
   Hit:4 http://deb.debian.org/debian-security trixie-security InRelease
   Get:5 http://deb.debian.org/debian trixie-backports/main arm64 Packages [292 kB]
   Reading package lists...
   Building dependency tree...
   Reading state information...
   All packages are up to date.

   Enable the matching backports suite first if apt update does not contact trixie-backports.
   Related: How to enable Debian backports

2. Check the stable and backports versions for the package.

   $ apt-cache policy tmux
   tmux:
     Installed: (none)
     Candidate: 3.5a-3
     Version table:
        3.6b-1~bpo13+1 100
           100 http://deb.debian.org/debian trixie-backports/main arm64 Packages
        3.5a-3 500
           500 http://deb.debian.org/debian trixie/main arm64 Packages

   The Candidate line still points to stable because priority 500 is higher than backports priority 100.

3. Simulate installing the package from the backports suite.

   $ sudo apt --simulate install tmux/trixie-backports
   Reading package lists...
   Building dependency tree...
   Reading state information...
   Installing:
     tmux
   
   Installing dependencies:
     libevent-core-2.1-7t64  libjemalloc2
   
   Summary:
     Upgrading: 0, Installing: 3, Removing: 0, Not Upgrading: 0
   Inst libevent-core-2.1-7t64 (2.1.12-stable-10+b1 Debian:13.5/stable [arm64])
   Inst libjemalloc2 (5.3.0-3 Debian:13.5/stable [arm64])
   Inst tmux (3.6b-1~bpo13+1 Debian Backports:stable-backports [arm64])

   Stop if the resolver proposes removals or newer dependencies that have not been reviewed for the host.

4. Install the selected package from backports.

   $ sudo apt install tmux/trixie-backports
   Reading package lists...
   Building dependency tree...
   Reading state information...
   Installing:
     tmux
   
   Installing dependencies:
     libevent-core-2.1-7t64  libjemalloc2
   
   Summary:
     Upgrading: 0, Installing: 3, Removing: 0, Not Upgrading: 0
     Download size: 822 kB
     Space needed: 2350 kB / 109 GB available
   
   ##### snipped #####
   Setting up tmux (3.6b-1~bpo13+1) ...

   Use sudo apt install -t trixie-backports tmux when the selected package needs backported dependencies too.

5. Verify the installed package origin.

   $ apt-cache policy tmux
   tmux:
     Installed: 3.6b-1~bpo13+1
     Candidate: 3.6b-1~bpo13+1
     Version table:
    *** 3.6b-1~bpo13+1 100
           100 http://deb.debian.org/debian trixie-backports/main arm64 Packages
           100 /var/lib/dpkg/status
        3.5a-3 500
           500 http://deb.debian.org/debian trixie/main arm64 Packages

   The installed version should be the one from trixie-backports, while unrelated packages continue to follow the normal stable policy.

6. Run the installed command's version check.

   $ tmux -V
   tmux 3.6b

   Replace the version check with the command or service check that proves the package you installed is usable.