Most of the software used in Kubuntu , is part of the KDE project , but all other software used in Ubuntu can also be used . Because the only difference of Kubuntu and Ubuntu is the default software , you can turn an Ubuntu system into a Kubuntu system , or a Kubuntu system into an Ubuntu system , only by installing some software . Because Kubuntu is Ubuntu with a KDE desktop , any version available in Ubuntu is also available for Kubuntu .