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MCP v2: What’s Changing, What’s Deprecated, and Why
MCP v2 breaking changes explained: the protocol goes stateless and deprecates sampling, roots, and logging. What is changing across every MCP SDK, why, and whether you should migrate yet. This article was originally published at Agentailor blog.
Introduction
If you have built anything on the Model Context Protocol, the next few weeks matter. MCP v2 (protocol revision 2026-07-28) finalizes on July 28, 2026. The release candidate was locked on May 21, 2026, and SDK maintainers are validating it against real workloads during a ten-week window before the spec is published.
This is not a point release. v2 makes the protocol stateless, formalizes extensions as first-class components, and deprecates three subsystems that many existing servers rely on: sampling, roots, and logging.
This article is the language-agnostic companion to our SDK-specific guides. It covers what is changing and why, so that when the stable SDKs land you understand the shape of the migration regardless of whether you write TypeScript, Python, Go, or C#. For the current v1 TypeScript walkthrough, see The MCP TypeScript SDK: A Complete Guide; a v2 update to that guide will follow once the SDKs reach stable.
Important: As of this writing the v2 SDKs are in beta. The MCP team is…
