Current optimistic model versioning systems, which are indispensable to coordinate the collaboration within teams, are able to detect several kinds of conflicts between two concurrently modified versions of one model. These systems support the detection of syntactical problems such as contradicting changes, violations of the underlying metamodel, and violations of OCL constraints. However, violations of the models’ semantics remain unreported. In this paper, we suggest to use redundant information inherent in multi-view models to check if the semantics is violated during the merge process. In particular, we exploit the information encoded in state machine diagrams to validate evolving sequence diagrams by means of the model checker SPIN.