  Context: Changes in the software development paradigm, when operated by
entities with a pivotal role, have the power to affect a number of groups and
entities in their sphere of influence, changing both their working habits and
relations.
  Objective: In this paper we present the organizational changes occurred in a
software ecosystem as consequence of a technological change. In particular we
examine the evolution of an MDD solution and the changing roles of the company
promoting it, the public administrations and the sub-contractors.
  Method: The paper focuses on a single case study that encompasses the six
years long evolution of a Model-driven development solution, starting from its
conception until is recent open-source release, across five distinct phases.
The history was analyzed jointly by software engineering academics and
industrial managers directly involved in the case study.
  Results: A report of the ecosystem evolution from an idiographic perspective
is reported. An analysis of the history allowed an abstraction that led to the
identification of several distinct ecosystem evolution motifs.
  Conclusion: The motifs represent a set of key process areas for the evolution
of a software ecosystem. They are potentially generalizable to other similar
ecosystems. As such, they can be used by researchers to evaluate existing
in-progress case studies, and by practitioners as a set of guidelines.
