Deprecated Features

specification/draft/deprecated New page · 39 lines, new page

# Deprecated Features ## Deprecated ## Removed

A whole new page. There's nothing to diff it against, so here is what it says.

# Deprecated Features

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This page is the registry of specification features that are currently in the
**Deprecated** state under the
[feature lifecycle and deprecation policy](/community/feature-lifecycle)
([SEP-2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596)).

A Deprecated feature remains part of the specification but is scheduled for
removal: new implementations **SHOULD NOT** adopt it, and existing
implementations **SHOULD** migrate before the feature's earliest removal. The
earliest removal marks when a feature becomes *eligible* for removal; the
actual removal is a Core Maintainer decision taken during release preparation
and may happen later.

This registry is a derived view kept consistent with the per-feature
deprecation notices and changelog entries, which are the normative records.

## Deprecated

| Feature                                                                                                                 | Deprecation SEP                                                                    | Deprecated in | Migration path                                                                                                            | Earliest removal                                                                                      |
| ----------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- | ------------- | ------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- |
| [Roots](/specification/draft/client/roots)                                                                              | [SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577) | `2026-07-28`  | Pass directories or files via tool parameters, resource URIs, or server configuration                                     | First revision released on or after 2027-07-28                                                        |
| [Sampling](/specification/draft/client/sampling)                                                                        | [SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577) | `2026-07-28`  | Integrate directly with LLM provider APIs                                                                                 | First revision released on or after 2027-07-28                                                        |
| [Logging](/specification/draft/server/utilities/logging)                                                                | [SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577) | `2026-07-28`  | Log to `stderr` for stdio transports; use [OpenTelemetry](https://opentelemetry.io/) for observability                    | First revision released on or after 2027-07-28                                                        |
| [Dynamic Client Registration](/specification/draft/basic/authorization/client-registration#dynamic-client-registration) | [PR #2858](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2858) | `2026-07-28`  | [Client ID Metadata Documents](/specification/draft/basic/authorization/client-registration#client-id-metadata-documents) | First revision released on or after 2027-07-28                                                        |
| `includeContext: "thisServer"` / `"allServers"` ([Sampling](/specification/draft/client/sampling#capabilities))         | [SEP-2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596) | `2025-11-25`  | Omit the field or use `"none"`                                                                                            | Follows Sampling ([SEP-2577](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2577)) |
| [HTTP+SSE transport](/specification/2024-11-05/basic/transports#http-with-sse)                                          | [SEP-2596](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2596) | `2025-03-26`  | [Streamable HTTP](/specification/draft/basic/transports/streamable-http)                                                  | Three months after SEP-2596 reaches Final                                                             |

The HTTP+SSE transport and the `includeContext` values were already described
as deprecated before the lifecycle policy existed; SEP-2596 reclassifies them
as Deprecated under its [transition provisions](/community/feature-lifecycle).

## Removed

No features have been removed under this policy yet. When a Deprecated feature
is removed, its row moves to this section with a link to the changelog entry
recording the removal.