Now that is near the exit of the new version of Ubuntu 9.04 Jaunty Jackalope going to remember how to do a version upgrade. First of all and as always recommended in these cases, we should back up our files and settings. For this, besides saving the files we have on our HOME we can save the list of packages as we have seen -generate-list-installed applications

Once the backup proceed to install the update package:

sudo apt-get install update-manager-core

entered our password download the necessary files to install in our system.

And once installed proceed to implementation with

sudo do-release-upgrade

This will start the update process. A process that used a long time depending on your Internet connection.