MCP Protocol's Largest Update: Shifting to Stateless on July 28

The Model Context Protocol (MCP) is set to finalize its largest specification update to date on July 28. The core change of this revision is a comprehensive shift from stateful to stateless, aimed at better supporting stateless load balancing and dynamic discovery. For developers, this eliminates the need for sticky sessions and favors horizontal scaling. This is not a standard patch but a substantial architectural migration.

Confirmed

To achieve statelessness, the new spec introduces several specific mechanisms:

Completely removed the original initialize handshake process and Mcp-Session-Id via SEP-2575.
Each request will inline carry its protocol version, client info, and capabilities via meta, adding Mcp-Method and Mcp-Name headers.
For scenarios where the server needs to initiate confirmations or other requests mid-call, a new MRTR (Multi Round-Trip Request) mechanism is introduced to replace the old state retention method.

Unconfirmed

According to developer @ialijr, this update deprecates the sampling feature, which some developers regretted. The community is currently actively discussing migration preparations and the specific impact.

Why it matters

The shift to statelessness brings significant scalability benefits but involves functional trade-offs. Developer @dfinke specifically clarified a key misconception: removing the protocol-layer session does not mean the application itself must become stateless. The changes primarily occur at the transport layer, and server applications can still maintain state using the MRTR mechanism.

2026-07-22 ~ 2026-07-23 · 9 related posts

Full story(4 episodes)→

Episode 1: MCP Protocol's Largest Update: Shifting to Stateless on July 28(2026-07-22, 9 posts)
Episode 2: MCP Releases Stateless Core Spec with Enterprise Extensions and Security Upgrades(2026-07-28, 27 posts)
Episode 3: DBHub Upgrades to Latest MCP Spec: Engineering Practices(2026-07-29, 2 posts)
Episode 4: MCP Protocol Undergoes Major Refactor: Shift to Stateless Architecture(2026-07-30, 5 posts)

Primary sources

Largest MCP Revision Goes Stateless, Drops Initialize Handshake and Session IDs — dfinke · 2026-07-22 03:11 (UTC+08:00)
MCP v2 Finalizes Next Week: Stateless, Sampling Deprecated, Developers Discuss Migration — ialijr · 2026-07-22 04:45 (UTC+08:00)
Protocol sessions go away, but apps can stay stateful with MRTR — dfinke · 2026-07-22 03:11 (UTC+08:00)

July 28 MCP update makes stateful servers stateless — dfinke · 2026-07-22
Largest MCP Revision Goes Stateless, Drops Initialize Handshake and Session IDs — dfinke · 2026-07-22
MCP Architecture Update: Enables Stateless Load Balancing and Dynamic Discovery — dfinke · 2026-07-22
Largest MCP spec update moves servers from stateful to stateless — dfinke · 2026-07-22
[source] Protocol sessions go away, but apps can stay stateful with MRTR — dfinke · 2026-07-22
[source] MCP v2 Finalizes Next Week: Stateless, Sampling Deprecated, Developers Discuss Migration — ialijr · 2026-07-22
MCP 2026-07-28 removes sessions and turns the protocol stateless — Substantial-Heat-321 · 2026-07-23
MCP spec will switch to stateless HTTP transport on July 28 — pjausovec · 2026-07-23

1 near-duplicate retellings: dfinke