Key Changes changedspecification/2025-03-26/changelog

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11# Key Changes

33This document lists changes made to the Model Context Protocol (MCP) specification since

4the previous revision, [2024-11-05](/specification/2024-11-05).

4the previous revision, [2024-11-05](/specification/2024-11-05.md).

66## Major changes

81. Added a comprehensive **[authorization framework](/specification/2025-03-26/basic/authorization)**

81. Added a comprehensive **[authorization framework](/specification/2025-03-26/basic/authorization.md)**

99 based on OAuth 2.1 (PR

1010 [#133](https://github.com/modelcontextprotocol/specification/pull/133))

11112. Replaced the previous HTTP+SSE transport with a more flexible **[Streamable HTTP

12 transport](/specification/2025-03-26/basic/transports#streamable-http)** (PR

12 transport](/specification/2025-03-26/basic/transports.md#streamable-http)** (PR

1313 [#206](https://github.com/modelcontextprotocol/specification/pull/206))

14143. Added support for JSON-RPC **[batching](https://www.jsonrpc.org/specification#batch)**

1515 (PR [#228](https://github.com/modelcontextprotocol/specification/pull/228))