In the area of component software, the work so far has con centrated primarily on the key issues of architecture specification and component updating. However, the problems of maintaining application consistency and versioning of components as they evolve have received less attention, and the available solutions are either ad-hoc or not well suited for component applications. In this paper we evaluate these solutions and present a new approach to component versioning developed for the SOFA architecture. Based on the analysis of changes between two versions, component revision numbers and change indications are derived as a lightweight compatibility description which is subsequently used for consistency verification during application composition or component update. Thus it is shown how giving the revision numbers a precise semantics and providing additional versioning information provides a support for the tasks of configuration management in component applications.