Ubuntu 8.04.4 LTS incorporates various bug-fixes and minor updates that have been made available since the release of Ubuntu 8.04.3 back in July. Notable updates for Ubuntu 8.04.4 is the contents of the CD ISO working from a USB device (like newer versions of Ubuntu already do), installation support where JFS file-systems are present, and a newer version of the Pidgin instant messaging application has been back-ported to Ubuntu Hardy. Ubuntu has since switched over to using GNOME Empathy as the default instant messaging program, but the older version of Pidgin found in Ubuntu 8.04 no longer worked with the Yahoo Instant Messaging protocol, which warranted pulling in a newer version of Pidgin.
The release announcement for Ubuntu 8.04.4 LTS can be found on ubuntu-announce with the various download links and notices. While this is the last ISO spin for the Ubuntu 8.04 series, server and desktop updates will continue to be offered through their Debian package repository.
Ubuntu 10.04 LTS "Lucid Lynx" will be released in April with an updated X stack, more paper-cuts healed, Plymouth integration, new server features, Nouveau kernel mode-setting, and many other new features and packages.