ubuntu 11.04

Upgrade from Ubuntu 10.10

To upgrade from Ubuntu 10.10 on a desktop system, press Alt+F2, type in "update-manager -d" (without the quotes), and press Enter. Update Manager will open up and display the message, "New distribution release '11.04' is available." Click Upgrade and follow the on-screen instructions. 

To upgrade from Ubuntu 10.10 on a server system, install the package update-manager-core if it is not already installed. Then execute the command sudo do-release-upgrade -d, and follow the on-screen instructions. Note that the server upgrade is now more robust, and thus will utilize GNU screen and automatically re-attach in case unexpected problems arise, e.g. dropped connection problems.

The same instructions apply to all other editions of Ubuntu (such as Kubuntu, Xubuntu, etc.)