Kubuntu 15.10 is the new stable version from the official Ubuntu subproject that features the latest KDE Plasma 5 desktop. Plasma 5, the next generation of KDE's desktop, has been rewritten to make it smoother to use while retaining the familiar setup. The fourth set of updates to Plasma 5 (current release, including the fixpack) is the default in this version of Kubuntu. Kubuntu comes with KDE Applications 15.08 containing all your favorite applications from KDE, including Dolphin. This is the first stability update, and it contains bug fixes and translation updates. 107 applications have been ported to KDE Frameworks 5 but those which aren't should fit in seamlessly. Non-KDE applications include LibreOffice 5.0 and Firefox 41.
About Kubuntu
Kubuntu is a free, user-friendly Linux distribution based on KDE's desktop software and on the Ubuntu operating system. It has a biannual release cycle. Besides providing an up-to-date version of the KDE desktop at the time of the release, the project also releases updated KDE packages throughout the lifetime of each release.