While an indicator of its vibrancy, the rapid evolution of a mobile ecosystem also causes challenges to mobile software engineers in developing and maintaining quality products, and to users concerning the usability and security of resulting apps. In this context, it is crucially important to arm mobile software engineers with effective and practical tool support that is informed and enabled by a comprehensive understanding of the evolutionary dynamics of this ecosystem. Targeting Android, we envision to build an infrastructure that is capable of systematically and continuously mining a mobile software ecosystem. Using this infrastructure, we then perform large-scale longitudinal characterization studies of the ecosystem to understand its evolutionary dynamics with a focus on the behavioral evolution patterns of, and ecological interaction among, three ecosystem elements: the mobile platforms, user apps built on the platforms, and users associated with the apps (including end users and developers). Further, the characterization results enable proactive app quality and sustainable app security. We also report our current progress in this effort with initial results, and discuss risks and next steps. CCS CONCEPTS • Software and its engineering → Software evolution; Maintaining software;