While health- and well-being-related online social and service platforms for supporting elderly peopole have been widely discussed conceptually in recent years, only few studies exist on the actual challenges of implementing such systems. In particular, the application of a user-centric design approach for the development of such systems has not been comprehensively analyzed so far. Therefore, in this paper the outcomes of the requirements engineering phase of the implementation of an online social and service network platform for elderly peopole in the so-called transition age between 55 and 75 are presented. The desired features and functionalities co-created with the prospective stakeholders of the system are illustrated, and lessons learned during the correspod-ing requirements engineering process are presented. While the approach has been found to be in principle feasible, special attention needs to be paid to limit the risks of creating overblown functionality and scope creep during the requirements engineering phase.