For eighteen months, running a remote MCP server meant fighting your own infrastructure. You had a bidirectional, stateful protocol sitting on top of HTTP, which meant sticky sessions, a shared Redis for session state, or a gateway doing packet inspection to route requests to the one box that held the connection. Every horizontal scaling story started with an apology.
On July 28, 2026, that ended. The 2026-07-28 specification makes MCP stateless at the protocol layer — the largest revision since launch, and the first one that makes MCP behave like the rest of the web.
What actually changed
Six SEPs (Specification Enhancement Proposals) work together here. The short version:
The handshake is gone. initialize/initialized and the Mcp-Session-Id header have been removed (SEP-2575, SEP-2567). Every request is now self-describing: protocol version, client identity, and client capabilities ride inline in _meta on each call. There's an optional server/discover RPC if a client wants capabilities up front, but nothing requires it.
