Ubuntu has more than 20 major releases. Sometimes we need to work with old and end-of-life ones. Here is some useful info on ubuntu releases.

Check current release

Use command:

lsb_release -a

And a sample output:

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.3 LTS
Release:        14.04
Codename:       trusty

List of releases

Version Code name Code name in /etc/apt/sources.list
Ubuntu 17.10 Artful Aardvark artful
Ubuntu 17.04 Zesty Zapus zesty
Ubuntu 16.10 Yakkety Yak yakkety
Ubuntu 16.04 LTS Xenial Xerus xenial
Ubuntu 15.10 Wily Werewolf wily
Ubuntu 15.04 Vivid Vervet vivid
Ubuntu 14.10 Utopic Unicorn utopic
Ubuntu 14.04 LTS Trusty Tahr trusty
Ubuntu 13.10 Saucy Salamander saucy
Ubuntu 13.04 Raring Ringtail raring
Ubuntu 12.10 Quantal Quetzal quantal
Ubuntu 12.04 LTS Precise Pangolin precise
Ubuntu 11.10 Oneiric Ocelot oneiric
Ubuntu 11.04 Natty Narwhal natty
Ubuntu 10.10 Maverick Meerkat maverick
Ubuntu 10.04 LTS Lucid Lynx lucid
Ubuntu 9.10 Karmic Koala karmic
Ubuntu 9.04 Jaunty Jackalope jaunty
Ubuntu 8.10 Intrepid Ibex intrepid
Ubuntu 8.04 LTS Hardy Heron hardy
Ubuntu 7.10 Gutsy Gibbon gutsy
Ubuntu 7.04 Feisty Fawn feisty
Ubuntu 6.10 Edgy Eft edgy
Ubuntu 6.06 LTS Dapper Drake dapper
Ubuntu 5.10 Breezy Badger breezy
Ubuntu 5.04 Hoary Hedgehog hoary
Ubuntu 4.10 Warty Warthog warty


Config sources.list for old releases

Edit /etc/apt/sources.list or create a new file in /etc/apt/sources.list.d/ with the following content:

deb http://old-releases.ubuntu.com/ubuntu/ codename main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ codename-updates main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ codename-backports main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ codename-security main restricted universe multiverse

Replace codename with the one of your release.

Then run the following to install the package you want.

sudo apt-get update
sudo apt-get install package

Note: This is only for end-of-life releases. Currently supported releases are not moved to old-releases.ubuntu.com