The new MCP spec eliminates sessions, moves client info to per-request _meta, and introduces requestState for server-side state that travels with requests. This changes how MCP servers are built. This talk covers: migrating from initialize/initialized to server/discover, replacing Mcp-Session-Id with requestState for stateful operations, using InputRequiredResult for multi-round-trip flows without SSE streams, implementing the new Mcp-Method and Mcp-Name headers for gateway routing, adopting ttlMs and cacheScope for list and resource responses, and handling the transition period where both old and new protocol versions coexist. We share migration patterns from a production self-hosted MCP registry that supports both protocol versions simultaneously.