Can a platform leader be challenged and loose its architectural control over its innovation ecosystem? The question seems absurd since theoretical works on modularity and multi-sided markets depict platform competitive landscapes as controlled by a hegemonic platform leader. However, platform history chronicles several cases of leadership shifts for the benefit of firms formerly providing complementary innovations. We coined these situations " platform overthrows ". To bridge the gap between classical optimization models and empirical evidences of platform overthrow, we rely on a design-theory-based model (Legrand et al. 2017) of platform dynamics to generate testable hypothesis. We then test them with a sample of 22 empirical cases of attempts of platform overthrow. Our results indicate that platform overthrows are always built by a challenger that introduces a new functional range in the ecosystem. However, the efforts of the challenger can be ruined if the technology of the platform leader is easily adaptable to the new functional range. Otherwise, the challenger can overthrow its platform leader if it succeeds in designing a technology that can address both the former and the new functions. We conclude by highlighting how studying both technological and functional evolutions can provide a thorough understanding of platform ecosystem dynamics.