The development of the next major version 3.0 of the international OGC standard CityGML is nearing its end. CityGML 3.0 will come up with a variety of new features and revisions of existing modules that will increase the usability of CityGML for more user groups and areas of application. This includes a new space concept, a revised level-of-detail (LOD) concept, the representation of time-dependent properties, the possibility to manage multiple versions of cities, the representation of city objects by point clouds, an improved modelling of constructions, the representation of building units and storeys, an improved representation of traffic infrastructure as well as a clear separation of the conceptual model and the data encodings that allow for providing further encoding specifications besides GML. This paper gives an overview of these new and revised concepts, and illustrates their application through selected use cases.