This paper is a brief comparison between the Interactions of UML 2.0 as defined by the Final Adopted Specification (OMG ptc/03-07-06) and MSC-2000 as defined by Z.120 (ITU 1999). The comparison investigates whether UML 2.0 has serious shortcomings relative to MSC-2000. The paper also discusses whether MSC-2000 is still needed in the future or should be retired.