- MCP’s new core removes protocol-level sessions and the initialization handshake, allowing requests to run behind standard load balancers without sticky routing or shared session stores. [1] - The specification introduces a minimum 12-month deprecation window; Roots, Sampling and Logging still work, but new implementations are advised against adopting them. [2] - The release strengthens OAuth handling, though MCP still cannot eliminate prompt injection, unsafe tools or excessive permissions by itself.
[3] The Model Context Protocol has completed its largest architectural rewrite since its 2024 launch, replacing mandatory connection state with self-contained requests that are easier to route, cache and trace across enterprise infrastructure.[1]
Under the July 28 specification, MCP clients no longer complete an initialize handshake or carry an Mcp-Session-Id. Protocol versions and client capabilities instead travel with each request, while a new server/discover method lets clients inspect a server before using it. Applications can retain state through explicit handles passed as tool arguments.[1]
A breaking change with a migration path #
The change breaks the newest wire format from earlier MCP revisions, but official SDKs can negotiate older versions for existing clients and servers. GitHub said its MCP server removed Redis-backed sessions and body inspection while its Go SDK retained backward compatibility; the official Go and C# SDKs have also shipped support for both protocol generations.[4]
MCP’s new governance policy should make later transitions less abrupt. Features now move through Active, Deprecated and Removed states, with at least 12 months between deprecation and possible removal. Roots, Sampling and Logging are deprecated but remain functional; recommended replacements include explicit resource parameters, direct model-provider integrations and OpenTelemetry.[2]
Broad support does not remove security work #
MCP already spans products and infrastructure from Anthropic, OpenAI, Microsoft, Google and AWS. Current deployments include coding assistants, internal workflow apps and managed cloud agents: ChatGPT is rolling out MCP write actions for business customers, while AWS offers authenticated access to its APIs and Google provides managed remote servers for its services.[5][6]
The revision adds issuer validation and binds saved client credentials to the authorization server that issued them, reducing OAuth mix-up and credential-reuse risks. [3] Deprecating Sampling and Roots may eventually shrink exposure to model-mediated data exfiltration and filesystem disclosure.
The specification still warns that tools can execute arbitrary code and that their descriptions are untrusted; enterprises remain responsible for consent, least-privilege access, auditing and server governance.
[[7]](https://modelcontextprotocol.io/seps/2577-deprecate-roots-sampling-and-logging)
[[8]](https://modelcontextprotocol.io/specification/2026-07-28)## Companies mentioned
Further sources #
[[1] Model Context Protocol, “Key Changes,” specification revision dated July 28, 20… ↗](https://modelcontextprotocol.io/specification/2026-07-28/changelog)
[[2] Model Context Protocol, SEP-2596: Specification Feature Lifecycle and Deprecati… ↗](https://modelcontextprotocol.io/seps/2596-spec-feature-lifecycle-and-deprecation)
[[3] Model Context Protocol, July 28, 2026 changelog, authorization changes includin… ↗](https://modelcontextprotocol.io/specification/2026-07-28/changelog)
[[4] GitHub, “GitHub MCP Server supports the next MCP specification,” July 23, 2026;… ↗](https://github.blog/changelog/2026-07-23-github-mcp-server-supports-the-next-mcp-specification/)
[5] Anthropic, “Donating the Model Context Protocol and establishing the Agentic AI… ↗
[6] OpenAI, ChatGPT developer mode and MCP apps documentation; AWS and Google Cloud… ↗+2 more The stories that matter, in one email. Free — unsubscribe anytime.