Ubuntu 7.04 fixes to end
Eighteen months ago, on the 19th of April 2007, Canonical released Ubuntu 7.04, "Feisty Fawn" assuring users that they would support the release with eighteen months of security and other critical fixes. That support period comes an end on the 19th of October; from that point on, there will be no references to 7.04 in Ubuntu Security notices. Users still running Ubuntu 7.04 are advised to upgrade.
Ubuntu's official upgrade path is to upgrade from 7.04 to 7.10, "Gutsy Gibbon". To upgrade to 8.04 LTS (Long Term Support), a user must upgrade to 7.10, then upgrade to 8.04. The instructions for upgrading to 7.10 are available on the Ubuntu web site, with notes on issues which may arise.
The current release, Ubuntu 8.04, "Hardy Heron", is a long term support release. Released in April 2008, there will be security and critical issue fixes for three years from that date for desktop systems and five years for server systems.