MCP v2 Stateless vs MCP v1 Stateful (2026): Spec Final, Core SDK Still on 1.30.0
MCP v2 stateless vs MCP v1 stateful, four days after the July 28 deadline: the specification tag is final and PyPI mcp is on 2.0.0, but @modelcontextprotocol/sdk is still 1.30.0. Compare scaling, SDK stability, authorization and migration risk.
Four days after the deadline the picture has changed twice over. The specification is final: the 2026-07-28 tag went non-prerelease at 16:47 UTC on July 28, so the governance objection to cutting over is gone. PyPI followed the same day — pip install mcp now resolves to 2.0.0 (uploaded 13:45 UTC on July 28), not the 1.28.1 that was still current on deadline morning. What has not moved is the core TypeScript SDK: @modelcontextprotocol/sdk is still 1.30.0, published 2026-07-27T17:56 UTC, and counting. So the split is no longer TypeScript versus Python; it is server packages and Python versus the one core TypeScript package that almost every custom client imports. Choose v2 Stateless now if you build MCP servers in TypeScript (the scoped @modelcontextprotocol/server, /node and /hono packages are 2.0.0 stable) or in Python, and if you need horizontal scaling without sticky sessions, restart-safe routing and clean serverless execution. Stay on v1 Stateful where you depend on @modelcontextprotocol/sdk itself — client code and anything built on the core SDK has no 2.x to install — or where your clients and adapters are untested against a stateless server. Pin either way: four scoped npm packages and PyPI's mcp all now resolve latest to 2.0.0, so an unpinned install crosses a major version by itself. And nothing broke on July 28: the Roots, Sampling and Logging deprecations are annotation-only for at least a year, so migrate deliberately, package by package.
Detailed Comparison
A side-by-side analysis of key factors to help you make the right choice.
| Factor | MCP v2 StatelessRecommended | MCP v1 Stateful | Winner |
|---|---|---|---|
| Horizontal scaling | Any request can be routed to any compatible server instance once the app keeps state outside the protocol server | Long-lived sessions and connection affinity are easier to reason about, but they complicate autoscaling and failover | |
| SDK stability | Shipped in stages: the scoped server packages went 2.0.0 stable on July 27 and PyPI mcp followed on July 28, but @modelcontextprotocol/sdk is still 1.30.0 — v2 is installable everywhere except the core TypeScript package | Still what you get from @modelcontextprotocol/sdk, and still the maintained line for bug and security fixes on that package | |
| Serverless and ephemeral hosting | Designed for short-lived request/response execution, so Vercel, Cloud Run, Lambda-style and container autoscaling patterns become cleaner | Works best when a process can keep session context alive; possible in serverless, but operationally awkward | |
| State management model | Forces state into explicit client context, shared stores or application databases, which is cleaner but requires refactoring | Lets server code keep conversational/session assumptions in memory, which is convenient for simple internal tools | |
| Ecosystem compatibility today | The specification is final and both the TypeScript server surface and Python are installable at 2.0.0, so a mixed-language stack can now move almost as one unit | Most existing examples, packages and internal servers still assume v1 behaviour, and anything importing the core TypeScript SDK has no alternative | |
| Authorization and governance | The final 2026-07-28 specification requires OAuth 2.0 Protected Resource Metadata (RFC 9728) to advertise the authorization server location, and bundles a formal deprecation policy into the protocol roadmap | Authorization can be governed at the gateway, but the protocol line is older and less explicit about the new model | |
| Migration risk | Now spread across both registries: an unpinned install can jump to 2.0.0 on four scoped npm packages and on pip install mcp without you asking, so version bounds and parallel testing are mandatory | Low if you pin — but the risk is live on npm and PyPI now, not just on npm | |
| Future-proofing | Aligned with a specification that is now final rather than a release candidate; the server packages and Python are already there and the core SDK is the only piece still to follow | A compatibility baseline with a named escape hatch (server-legacy), but one that shipped already deprecated | |
| Total Score | 5/ 8 | 1/ 8 | 2 ties |
Key Statistics
Real data from verified industry sources to support your decision.
npm registry (@modelcontextprotocol/server)
modelcontextprotocol/modelcontextprotocol GitHub releases
npm registry (@modelcontextprotocol/sdk)
PyPI (mcp)
npm registry (@modelcontextprotocol/server-legacy)
modelcontextprotocol/python-sdk GitHub
Model Context Protocol Blog
Model Context Protocol Authorization Spec
All statistics come from verified third-party sources. Source, year, and direct link are shown on each metric.
When to Choose Each Option
Clear guidance based on your specific situation and needs.
Choose MCP v2 Stateless when...
- You ship MCP servers in TypeScript (@modelcontextprotocol/server 2.0.0) or in Python, where pip install mcp now resolves to 2.0.0
- You need horizontal scaling without sticky sessions, or serverless and ephemeral hosting for remote tools
- You can move session state into clients, databases or shared stores before cutover
- Your governance required a final specification tag before cutover — the 2026-07-28 tag is now final, not a release candidate
Choose MCP v1 Stateful when...
- Your code imports @modelcontextprotocol/sdk directly: it is still 1.30.0 and has no 2.x release to install
- Your server logic still relies on long-lived sessions, or your clients and adapters are untested against a stateless server
- You run pinned v1 infrastructure where an in-place major upgrade is riskier than the scaling headroom you would gain
- Your rollout process requires client tooling and servers to sit on the same major version
Our Recommendation
Four days after the deadline the picture has changed twice over. The specification is final: the 2026-07-28 tag went non-prerelease at 16:47 UTC on July 28, so the governance objection to cutting over is gone. PyPI followed the same day — pip install mcp now resolves to 2.0.0 (uploaded 13:45 UTC on July 28), not the 1.28.1 that was still current on deadline morning. What has not moved is the core TypeScript SDK: @modelcontextprotocol/sdk is still 1.30.0, published 2026-07-27T17:56 UTC, and counting. So the split is no longer TypeScript versus Python; it is server packages and Python versus the one core TypeScript package that almost every custom client imports. Choose v2 Stateless now if you build MCP servers in TypeScript (the scoped @modelcontextprotocol/server, /node and /hono packages are 2.0.0 stable) or in Python, and if you need horizontal scaling without sticky sessions, restart-safe routing and clean serverless execution. Stay on v1 Stateful where you depend on @modelcontextprotocol/sdk itself — client code and anything built on the core SDK has no 2.x to install — or where your clients and adapters are untested against a stateless server. Pin either way: four scoped npm packages and PyPI's mcp all now resolve latest to 2.0.0, so an unpinned install crosses a major version by itself. And nothing broke on July 28: the Roots, Sampling and Logging deprecations are annotation-only for at least a year, so migrate deliberately, package by package.
Frequently Asked Questions
Common questions about this comparison answered.
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