Mopsa is a multilanguage static analysis platform relying on abstract interpretation. It is able to analyze C, Python, and programs mixing these two languages; we focus on the C analysis here. It provides a novel way to combine abstract domains, in order to offer extensibility and cooperation between them, which is especially beneficial when relational numerical domains are used. We present the results of our 3-year participation to the international Software-Verification Competition, and reflect on future work.