European defence officials call for earlier interoperability testing and open architectures

European defense officials at Apex Europe 2026 called for open system architectures and earlier prototype testing to expose interoperability problems before equipment is widely fielded. Discussions focused on integrating crewed and uncrewed systems, cross-domain command and control, and resilience against cyber and electronic-warfare disruption. A NATO divisional commander cited allied forces in Latvia operating equipment that does not always work together and described an experimental cell for testing fielded systems. The remarks set priorities for procurement and operational trials; they do not announce a single new multinational contract or certified common architecture.