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You are running Debian stable, because you prefer the stable Debian tree. It runs great, there is just one problem: The software is a little bit outdated compared to other distributions. That is where backports come in.

Backports are recompiled packages from testing (mostly) and unstable (in a few cases only, e.g. security updates), so they will run without new libraries (wherever it is possible) on a stable Debian distribution. It is recommended to pick out single backports which fit your needs, and not to use all backports available.

Configuring your stable system

Verifying backports

In order to verify the integrity of downloaded backports before installing them, apt needs the archive key. The package debian-backports-keyring contains this key. So you should install it first.

Adding the repository

Using Synaptic

   Configuration > Repository

Using the command line

Become root and open the file /etc/apt/sources.list in your favorite editor:

human@debian:~$ su
debian:/home/human# nano /etc/apt/sources.list

Add the following lines:

# repository
deb lenny-backports main contrib non-free

If you are a free software enthusiast, you might want to remove the contrib and non-free sections. (See Debian sections for details.)

Now that you have added the repository, update apt's cache to include the backports in the list of available packages:

debian:/home/human# aptitude update


Using backports

Finding backports

There are a several different ways to find out if a backport of a certain Debian package exists. A pretty convenient one is using Debian's web-based package search ( If you are running Iceweasel, simply use the built-in search plugin (Deb Search).

Installing backports on the command line

The backports repository is deactivated by default. So, if you want to install a backported package, you will have to state that explicitly.

For example:

debian:/home/human# aptitude -t lenny-backports install iceweasel

The -t option here specifies lenny-backports as the target release. This would install Iceweasel 3.5 from instead of version 3.0 from the Debian stable release.

Automatic upgrades

Because the repository is deactivated by default, your installed backports won't recieve upgrades automatically. However, you can use pinning to cause APT to perform automatic upgrades. Pinning basically means controlling which version of which package is to be selected for installation. (See the APT HOWTO and man apt_preferences for in-depth explanation.)

In order to make APT perfom automatic upgrades of installed backports, follow these steps:

  1. Open the file /etc/apt/preferences in an editor of your choice.

  2. Insert the text below.
  3. Save and exit.

Package: *
Pin: release a=lenny-backports
Pin-Priority: 200

After changing APT's behavior in that file, it will act like this:

If a package was installed from and there is a newer version there, it will be upgraded from there. Other packages that are available from will not be upgraded to the version unless explicitly stated with -t lenny-backports.

External links