The Unified Modeling Language (UML) has been widely accepted throughout the software industry and successfully applied to diverse domains ever since it was adopted by the Object Management Group (OMG) in 1997. This article discusses the UML 2.0 major revision and explains that it represented both an excellent opportunity and a serious responsibility for its language designers. It is a chance for them to resolve the shortcomings of UML 1.x and make the language more current and precise.