Brosch, PetraSeidl, MartinaWieland, KonradWimmer, Manuel2017-04-152017-04-152009978-1-84882-854-4For the versioning of code a pantheon of version control system (VCS) solutions has been realized and is successfully applied in practice. Nevertheless, when it comes to merging two different versions of one artifact, the resolution of conflicts poses a major challenge. In standard systems, the developer who performs the later commit is sole in charge of this often time-consuming, error-prone task. This commit carries the inherent danger of losing the modifications of the other developer. Recently, collaborative merge approaches for code versioning systems have been proposed to minimize this risk. In this paper we propose to apply similar techniques in the context of model versioning where the challenge of merging two versions is even more formidable due to their graph-structure and their rich semantics. In particular, modeling is used in the early phases of the software development, where aenText10.1007/978-1-84882-854-4_12