S. T. Carvalho, L. Murta, O. Loques. "Variabilities as First-Class Elements in Product Line Architectures of Homecare Systems" Proceedings of the 4th International Workshop on Software Engineering in Health Care (SEHC 2012), 34th International Conference on Software Engineering (ICSE 2012), Zurich, Switzerland, 2012, pp. 33-39. Abstract A homecare system should adapt to changes regarding the patient needs and to variations in the residential environment. This requires a software architecture designed to support customizations before the deployment (static variability) and changes during the system operation (dynamic variability). We present a comprehensive approach in which both kinds of variabilities are seamless described by means of contracts, which are first-class elements associated with a Product Line architecture. To demonstrate the proposed approach, we present a dynamic contract developed to support a context-aware patient reminder application. Keywords: homecare systems; SPL architecture; static variability; dynamic variability; software architecture.