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Core ConceptProtocol Negotiation Layer

MCP Protocol Version

Industry Definition Set • Entity Resolution Path: /glossary/mcp-protocol-version

Quick Answer / TL;DR

The negotiated version of the Model Context Protocol used for a client-server session, ensuring both sides speak the same dialect.

Key Takeaways

  • Negotiated during the initialize handshake.
  • Uses semantic versioning.
  • Mismatched versions may cause session failure.
  • Always specify the supported version in client/server configs.
Definitive Statement: The negotiated version of the Model Context Protocol used for a client-server session, ensuring both sides speak the same dialect.

Technical Context & Protocol Usage

Detailed Explanation
MCP uses semantic versioning. During initialization, the client proposes a version and the server responds with its supported version. If they differ, the session may fall back to the lowest common version or fail to establish. Servers and clients should document which MCP versions they support.

Format & Payload Metadata

Format: Semantic version string (e.g., `2024-11-05`)

Latency: Evaluated once at session start

Real-World Implementation Use Case

A client requests MCP version `2024-11-05`; the server supports `2024-11-05` and confirms the session can proceed.

M
MCPserver.in Engineering

Platform Team

Published: 2026-07-20
Updated: 2026-07-20

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MLA Style:

MCPserver.in Engineering. "MCP Protocol Version." MCPserver.in Knowledge Hub, 20 July 2026, mcpserver.in/glossary/mcp-protocol-version.