The Model Context Protocol (MCP) has released its latest specification, 2026-07-28, marking a significant shift from a stateful to a stateless protocol. This update, accompanied by new SDKs for Type Script, Python, Go, and C#, aims to enhance reliability and scalability for MCP servers.

The core change is the transition to a request/response model, eliminating the need for bidirectional streams and session IDs. Each request is now self-describing, carrying necessary information within its metadata, allowing any server instance to handle it. This facilitates easier load balancing and improves resilience. For scenarios requiring state, developers can now use explicit handles passed as tool arguments.

Further enhancements include Multi Round-Trip Requests (MRTR) to manage mid-call user inputs, header-based routing for simpler gateway integration, and cache hints for list responses to optimize client caching. The release also formalizes an extensions framework, introduces authorization hardening measures like RFC 9207 issuer validation, and deprecates Dynamic Client Registration in favor of Client Metadata Documents (CIMD). The Type Script and Python SDKs have collectively surpassed 1 billion downloads, highlighting the protocol's growing adoption.