Code should aim to port away from this framework eventually. The API documentation of the classes in this framework and the notes at http://community.kde.org/Frameworks/Porting_Notes should help with this.
Note that some of the classes in this framework, especially KStandardDirs, may not work correctly unless any libraries and other software using the KDELibs 4 Support framework are installed to the same location as KDELibs4Support, although it may be sufficient to set the KDEDIRS environment variable correctly.