Enable backports in Debian 11

Sometimes the packages in Debian stable are way too old. In that case, you can use the backported repository to install packages in newer versions. It is not recommended to install every single package from the backported repo to keep your distro stable in the long term.

Instead only pick packages you need. Use the -t option with apt to force installation from the backported repo.

Enable backports in Debian

Open /etc/apt/sources.list in your favorite editor.

$ sudo vi /etc/apt/sources.list

Add a line containing the following:

deb http://deb.debian.org/debian bullseye-backports main

Update apt configuration

$ sudo apt update

Check apt pritority configuration and make sure the backports repo has lower priority than the other repositories.

$ apt-cache policy

Package files:
 100 /var/lib/dpkg/status
     release a=now
 500 https://nginx.org/packages/mainline/debian bullseye/nginx amd64 Packages
     release v=11.0,o=nginx,a=stable,n=bullseye,l=nginx,c=nginx,b=amd64
     origin nginx.org
 100 http://deb.debian.org/debian bullseye-backports/main amd64 Packages
     release o=Debian Backports,a=bullseye-backports,n=bullseye-backports,l=Debian Backports,c=main,b=amd64
     origin deb.debian.org
 500 http://security.debian.org/debian-security bullseye-security/main amd64 Packages
     release v=11,o=Debian,a=stable-security,n=bullseye-security,l=Debian-Security,c=main,b=amd64
     origin security.debian.org
 500 http://deb.debian.org/debian bullseye/main amd64 Packages
     release v=11.0,o=Debian,a=stable,n=bullseye,l=Debian,c=main,b=amd64
     origin deb.debian.org
Pinned packages:

As you can see, the backported repo has lower number than the rest. It is a bit more complicated than that (you can check apt's man page), but for the purposes of this, let's just say that lower means lower priority.