Business-to-Business (B2B) relationships have long been defined as critical means to manage competition and costs for partnering organizations. Inter-Organizational Information Systems (IOIS) have largely been endorsed as B2B enablers, and their middleware components have become critical in integrating processes in heterogeneous systems from different partners. To remain in sync with continuous change of requirements in business environment, processes in these middleware components require continuous lifecycle management from design to retirement. While this is often feasible, replacing legacy processes can be costly, complicated, and discouraging. This research utilizes a multimethodological approach that interweaves Design Science and Action Research to propose a roadmap for upgrading legacy processes in middleware components of IOIS. The proposed roadmap is generic and customizable to different organizational contexts.