Ubgrade ubuntu from 7.04 feisty

I am using Ubuntu Server 7.04 and I want to upgrade but I get the following errors.

How can I upgrade?

MY DISTRIBUTION:
Distributor ID: Ubuntu
Description: Ubuntu 7.04
Release: 7.04
Codename: feisty

Errors:

Code:

apt-get update

(I have read that this vesion is no longer supported)

Code:

do-release-upgrade

 

I guess the problem is that Feisty is too old. I guess the repositories don't exist anymore...