This study examines how digital platform owners can widen the scope for contributions from complementors with varying capacities. Empirically, we study the case of District Health Information Software 2 (DHIS2), an open-source platform for social development in low- and middle-income countries. Drawing on complementor engagement literature and commons-based peer production framework, this paper explores how DHIS2 offers channels for modular, granular, and low-cost integration of contributions allowing broad participation. We identify five channels for contributions: community of practice, roadmap, app hub, direct communication channels, and events. Each channel enables various contributions which positively impact the platform and other complementors. We also explain how each channel emerged from challenges related to enabling contributions and participation. We discuss how these channels enable broad participation and engagement of complementors to the platform ecosystem. The study contributes to practice and theory, offering insights into enabling diverse contributions in digital platforms for social development.