Metamodel deprecation to manage technical debt in model co-evolution.

Model-Driven Engineering helps formalize problem-domains by using metamodels. Modeling ecosystems consisting of purposely designed editors, transformations, and code generators are defined on top of the metamodels. Analogously to other software forms, metamodels can evolve---consequently, the validity of existing artifacts might be compromised. Coupled evolution provides techniques for restoring artifacts' validity in response to metamodel evolution. In this paper, we propose using deprecation in metamodeling to mitigate the difficulties in performing a class of adaptations that must be operated manually. Technical debt in co-evolution can be regarded as the outcome of procrastinating the migration of artifacts and, thus, must be reduced if not eliminated. Tool support for the adoption of deprecation and technical debt is used to demonstrate the feasibility of the methods.