Fix apt on old unsupported Ubuntu releases

After discovering an old server that was still running Ubuntu 11.10 I found that apt-get was no longer working as support for this version ended 9 months after it was released, quite some time ago!

I was seeing errors from apt-get update like:

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/oneiric-security/main/source/Sources  404  Not Found

And errors from apt-get upgrade like:

Err http://archive.ubuntu.com/ubuntu/ oneiric-updates/main ncurses-bin i386 5.9-1ubuntu5.1
403  Forbidden

Since the server isn't quite ready to be replaced I had to find a temporary solution.

Luckily ubuntu provides a repository for old releases, aptly named old-releases.ubuntu.com.
To use it, open /etc/apt/sources.list with your favourite text editor (you'll need to be root or use sudo) and replace all occurrences of archive.ubuntu.com or security.ubuntu.com with old-releases.ubuntu.com.

My sources.list now looks like this:

deb http://old-releases.ubuntu.com/ubuntu/ oneiric main
deb-src http://old-releases.ubuntu.com/ubuntu/ oneiric main
deb http://old-releases.ubuntu.com/ubuntu/ oneiric-updates main
deb-src http://old-releases.ubuntu.com/ubuntu/ oneiric-updates main
deb http://old-releases.ubuntu.com/ubuntu/ oneiric universe
deb-src http://old-releases.ubuntu.com/ubuntu/ oneiric universe
deb http://old-releases.ubuntu.com/ubuntu/ oneiric-updates universe
deb-src http://old-releases.ubuntu.com/ubuntu/ oneiric-updates universe
deb http://old-releases.ubuntu.com/ubuntu oneiric-security main
deb-src http://old-releases.ubuntu.com/ubuntu oneiric-security main
deb http://old-releases.ubuntu.com/ubuntu oneiric-security universe
deb-src http://old-releases.ubuntu.com/ubuntu oneiric-security universe

After you have updated the sources run an update:

$ sudo apt-get update

If you're still getting any 404 or 403 errors then double check your sources are correct. Otherwise you should now be able to upgrade your packages:

$ sudo apt-get upgrade

The above solution should work for Ubuntu releases as old as 4.10 (warty), though I haven't tested this.

You can avoid this problem in the future by using only LTS (long term support) releases which are supported for 5 years.