How to Install / Upgrade: Announcing v2.0 of the official MCP C# SDK

Announcing v2.0 of the official MCP C# SDK

MCP C# SDK v2.0 implements the 2026-07-28 specification. It brings a stateless-first protocol, standardized HTTP headers, and Multi Round-Trip Requests for interactive tools. The release stays backward compatible with existing usage.

To install or upgrade, move your project to the official MCP C# SDK v2.0 release. Because the SDK is backward compatible, you can upgrade in place without redesigning current integrations built on the prior surface. After the upgrade, rely on the new protocol behavior, standardized HTTP headers, and Multi Round-Trip Requests where your tools need interactive multi-step flows.

Gotchas are limited by the backward-compatible design: existing code should continue to work, but anything that assumed older session or header behavior should be rechecked against the 2026-07-28 specification and the stateless-first model. Verify the upgrade by confirming you are on MCP C# SDK v2.0, that standardized HTTP headers are in use, and that interactive tools that need Multi Round-Trip Requests complete their multi-step exchanges as expected.