KDE 4 is based on Qt 4 which is also released under the GPL for Windows and Mac OS X. Therefore KDE 4 applications can run natively on these operating systems as well. KDE 4 includes many new technologies and technical changes. The centerpiece is a redesigned desktop and panels collectively called Plasma which integrates Kicker, KDesktop, and SuperKaramba and is intended to update the decades-old desktop metaphor. There are a number of new frameworks, including Phonon, a new multimedia interface making KDE independent of any one specific media backend, Solid, an API for network and portable devices, and Decibel, a new communication framework to integrate all communication protocols into the desktop. Also featured is a metadata and search framework, incorporating Strigi as a full-text file