Gateway API v1.5, released March 14, 2026, marks their most significant release to date. This version focuses on promoting several formerly experimental features to the stable channel. Key promotions include ListenerSet, TLSRoute, HTTPRoute CORS Filter, Client Certificate Validation, Certificate Selection for Gateway TLS Origination, and ReferenceGrant. The project has adopted a release train model, synchronizing with Kubernetes SIG Release for more predictable updates. This new process includes dedicated Release Manager and Release Shadow roles. ListenerSet allows listeners to be defined independently and merged onto Gateways, enhancing scalability and multi-tenancy. TLSRoute enables routing based on SNI for TLS connections, supporting both Passthrough and Terminate modes. The HTTPRoute CORS filter provides granular control over cross-origin resource sharing settings. Client certificate validation, or mutual TLS (mTLS), allows Gateways to verify client identities by checking certificates against trusted CAs. This feature can be configured globally or per-port for enhanced security.