In this deliverable, CSEM and QC demonstrate encapsulated perovskite/Si tandem solar cells passing the IEC 61215 test criteria for damp heat, thermal cycling, thermal cycling combined with humidity freeze and UV pre-conditioning. Tandems of 4 cm² (CSEM) or M10 (331 cm², QC) were shown to degrade in power by less than 5%rel in these conditions. Importantly, QC demonstrated the successful pass of DH1000, TC200, HF10 and UV15 IEC tests as described earlier in the newsletter. The TC test is essential for validating layer adhesion, interconnect robustness and encapsulation performance and passing TC200, among passing DH1000, HF10 and UV15 tests, is a major milestone for industrial readiness. Furthermore, CSEM and HZB conducted ISOS L light soaking tests, notably to investigate the impact of the contact materials on the operational stability of perovskite solar cells.