Ubuntu end of life

It's always better to install a Ubuntu LTS as the other ones after one year apt-get stops working:

• 10.04
• 12.04
• 14.04
• 16.04
• 18.04

http://www.ubuntu.com/info/release-end-of-life

Update sources.list when apt-get does not work anymore

sudo nano /etc/apt/sources.list

then comment out all your repos, and use this(substitute maverick with the old code of your outdated ubuntu):

## EOL upgrade sources.list
# Required
deb http://old-releases.ubuntu.com/ubuntu/ maverick main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ maverick-updates main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ maverick-security main restricted universe multiverse
# Optional
#deb http://old-releases.ubuntu.com/ubuntu/ maverick-backports main restricted universe multiverse

Upgrade Ubuntu to the next release

Add the old-releases.ubuntu.com in sources.list as explained above then install the manager

sudo apt-get install update-manager-core

Next you can upgrade to the next version by using

sudo do-release-upgrade

After you are upgraded you can "sudo do-release-upgrade" again and again until you hit a supported version.

more info: https://help.ubuntu.com/community/EOLUpgrades and: http://www.westernwillow.com/cms/blog/franco/upgrading-old-or-end-life-eol-release-ubuntu-back-usefulness