During January 2026, Mantas Matelis developed TLS Handshake Filter State Management for the envoyproxy/envoy repository, focusing on enhancing downstream TLS handshake processing. He implemented logic in C++ to set filter state during the handshake, enabling the propagation of client SAN information to upstream listeners. This approach allows for more accurate connection management and policy enforcement by leveraging client identity at handshake time. Mantas also created integration tests to validate SAN propagation, updated documentation to describe the new behavior, and revised release notes. His work demonstrated depth in TLS, filter design, and network programming, improving reliability and security in TLS-based routing.