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On July 28, 2026, the Model Context Protocol team shipped the 2026-07-28 specification — officially, not as a release candidate. We covered the RC when it locked in June with the full breaking-changes list and migration checklist; that piece still holds for the mechanics. This one covers what changed between “here’s what’s coming” and “it’s live”: the final spec ships the same feature set the RC previewed, all four Tier 1 SDKs shipped support the same day, and the MCP team published real adoption numbers along with on-record statements from the companies building on it.

The headline number: growth since the last release

Per the MCP team’s own release post, Tier 1 SDKs (TypeScript, Python, Go, C#) are now pulling “close to half-a-billion downloads a month," and the TypeScript and Python SDKs have individually “crossed the 1 billion total downloads threshold." That’s the growth context the team gives for why a stateless rewrite mattered enough to ship as “MCP’s most important [release] since remote MCP first launched over a year ago” — the protocol outgrew the session-based design it launched with.

What’s actually in it (confirmed final, not just RC)

The final spec locks in everything the RC previewed back in May:

  • No handshake, no sessions. The initialize/initialized exchange and Mcp-Session-Id header are retired. Every request carries its own protocol version and client identity in _meta, so any request can land on any server instance behind a plain round-robin load balancer — no sticky routing, no shared session store.
  • Multi Round-Trip Requests (MRTR) replace the server-initiated elicitation/create, sampling/createMessage, and roots/list calls that used to require a held-open stream. A server that needs mid-call user input now returns resultType: "input_required", and the client retries with the answer attached — stateless-compatible by construction.
  • Header-based routing. Mcp-Method and Mcp-Name are now mandatory HTTP headers on Streamable HTTP requests, so gateways and WAFs can route and meter on headers instead of parsing JSON bodies.
  • Cacheable list results. tools/list, prompts/list, resources/list, and resources/read responses now carry ttlMs and cache scope.
  • Authorization hardening. RFC 9207 issuer validation is required, Dynamic Client Registration is formally deprecated in favor of Client ID Metadata Documents, and client credentials are bound to the issuer that minted them.
  • A formal extensions framework, with Tasks moving out of experimental core into io.modelcontextprotocol/tasks, alongside MCP Apps and Enterprise-Managed Authorization as separate tracked extensions.
  • A 12-month minimum deprecation window going forward — Roots, Sampling, and Logging are deprecated in this release but keep working for at least a year.

If you run a remote MCP server or maintain a client, see our RC coverage for the full migration checklist — the feature list above matches what shipped.

Who’s actually building on it

The release post is unusually thick with named, on-record statements from companies already shipping against the final spec — worth reading as adoption signal, not just a changelog:

  • AWS is shipping the stateless core in Amazon Bedrock AgentCore, and contributed the Tasks extension. Swami Sivasubramanian, VP of Agentic AI at AWS, said Tasks “brings support for reliable, long-running agents, so developers can spend less time on infrastructure and more time innovating.”
  • Cloudflare’s Agents SDK supports the spec “from day zero,” letting developers run MCP servers directly in Workers without transport-session overhead — per Brendan Irvine-Broque, Senior Director of Product Management at Cloudflare, who noted Cloudflare customers Sentry and Linear can adopt the same improvements immediately since MCP is an open standard.
  • Figma VP of Engineering Josh Clemm said the stateless architecture lets Figma’s MCP server “scale with” growing usage of generated outputs on Figma’s canvas.
  • Google Cloud Engineering Fellow Anna Berenberg called the stateless architecture “a massive leap forward in enterprise AI scalability” for the company’s developer-tools ecosystem.
  • honeycomb.io Director of AI Strategy Austin Parker disclosed that “nearly 20% of all monthly interactive queries are now made by agents” on Honeycomb’s platform — a Honeycomb-reported figure, not an MCP-team estimate — and said the new spec lets Honeycomb support “more advanced features such as elicitations while running at enterprise scale.”
  • Microsoft Foundry Corporate VP of Engineering Tina Schuchman said MCP is “foundational” to Foundry’s ability to “scale from dozens of integrations to thousands,” citing the Foundry toolbox’s unified MCP endpoint for governance, identity, and observability.
  • Manufact CTO Enrico Toniato said the new SDK’s client-server split “helped us cut the package size by around 83% while making it 25% faster” in mcp-use, the company’s open-source framework.
  • FastMCP CEO Jeremiah Lowin said the release is “a milestone” for anyone building MCP at scale and confirmed FastMCP 4.0 will ship “first-class support for background tasks, stateless interactivity, enterprise auth, and more.”
  • Supabase Head of Product Inian Parameshwaran said MRTR finally makes elicitation practical for a service that “runs statelessly” — Supabase can now confirm destructive actions (like deleting data) with the user mid-call.
  • Anthropic VP of AI Andrew Goodman said the stateless core “reduces the complexity we manage, so we can ship more features to our customers, faster and at scale.”

All of the above are direct quotes from named individuals in the MCP team’s own release post — read the full post for the complete list of contributor statements (Netlify, Runlayer, and others are also quoted).

What this means if you’re building

Nothing in this release changes your migration math from what we laid out when the RC locked — if you haven’t started, start now. What’s new as of July 28:

  1. It’s no longer provisional. All four Tier 1 SDKs (TypeScript, Python, Go, C#) speak 2026-07-28 as of release day, with the Rust SDK in beta. Pin to the new spec version with confidence — this isn’t going to shift under you.
  2. The 12-month deprecation clock started July 28, not whenever you get around to migrating. Roots, Sampling, Logging, and legacy HTTP+SSE transport still work today but are on a dated offramp.
  3. If you were waiting to see whether major infra providers would actually adopt the stateless model before committing your own server, that signal is now in writing from AWS, Cloudflare, and Google Cloud simultaneously — not just the protocol maintainers.