MCP 2026-07-28 ships: sessions gone, extensions in, 400M downloads a month
The Model Context Protocol's biggest revision since launch rips out stateful sessions, formalizes Tasks and MCP Apps as extensions, and lands across Tier 1 SDKs today.
The Model Context Protocol shipped its 2026-07-28 revision today, and the headline change is a subtraction: protocol-level sessions are gone. MCP is now a stateless request/response protocol, with routing information mirrored into HTTP headers so load balancers can dispatch traffic without inspecting the payload or tracking session state.
Lead maintainers David Soria Parra and Den Delimarsky framed the stateless core as “one of the most highly-requested features” from developers who wanted reliability and scalability. Soria Parra, speaking on a July 23 Register livestream, was blunter about the scope: this is the “most substantial changes we have made to the specification, probably since adding authorization.” His other summary: “A lot of things that made MCP are gone.”
All four Tier 1 SDKs speak the new spec as of release, with the Rust SDK arriving in beta. Anthropic is reporting more than 400 million monthly SDK downloads, a 4x jump this year, with the TypeScript and Python SDKs each past a billion lifetime downloads. Claude’s connectors directory now lists over 950 servers.
Around the stateless core, the extensions framework is doing real work. Tasks, contributed by AWS, graduates to a formal io.modelcontextprotocol/tasks extension under SEP-2663, with tasks/get for polling and a new tasks/update method. MCP Apps is formalized in the same framework. Roots, Sampling, Logging, and the legacy HTTP+SSE transport are all deprecated under SEP-2577 on a 12-month offramp. Dynamic Client Registration gives way to CIMD.
Day-zero support lands from Amazon Bedrock AgentCore, Cloudflare Workers, Microsoft Foundry, Google Cloud, and Netlify. Stacklok’s enterprise readiness guide, cited by The Register, cautions that the deprecation window is “not a blanket guarantee of interoperability”; 2026-07-28 servers talking to older clients still need deliberate fallback logic.
The pattern rhymes with Python 3’s long compatibility tail after 2008: a protocol that scales by shedding what made it distinctive.
Sources
- https://blog.modelcontextprotocol.io/posts/2026-07-28/
- https://claude.com/blog/bringing-mcp-2026-07-28-to-claude
- https://modelcontextprotocol.io/specification/2026-07-28
- https://www.theregister.com/devops/2026/07/23/model-context-protocol-prepares-to-break-with-its-stateful-past/5276722
- https://www.infoworld.com/article/4201254/model-context-protocol-is-going-stateless-to-make-scaling-simpler.html