Upgrading to Ubuntu(9.10) Karmic Koala from the Jaunty Jackalope(9.04) build is pretty easy. Ubuntu having a 6 month release cycle has been very wise to provide an easy upgrade option.
This guide will let users upgrade to Ubuntu Karmic Koala using the GUI provided for distribution upgrades which can be accessed at:
System > Administration > Update Manager. This upgrade needs root privileges.
You will get a window informing about the availability of the version 9.10. Click on upgrade.
Go through the release notes to know about changes. Click on Upgrade again when done.
Next, the files needed for the upgrade are fetched.
After the files are successfully fetched, you are prompted to start the upgrade process. The upgrade takes quite some time depending on the number of packages you are using and whether you update regularly.
Once the updates are installed and the distro version is upgraded, you are prompted to restart your system. After a restart, you will see the version 9.10 as your version number.