---
title: "4. Versioning"
description: "MCP Description specification v0.7.0 — 4. Versioning."
source: "https://mcpdesc.org/docs/specification/0.7.0/versioning/"
---

Mirrored specification

This page mirrors **4\. Versioning** of the MCP Description specification **v0.7.0**. The canonical source of truth is [cisco-open/mcptoolkit-contract](https://github.com/cisco-open/mcptoolkit-contract/blob/main/spec/sections/04-versioning.md). Where this page differs from upstream, upstream wins.

## 4\. Versioning

### 4.1 The `mcpdesc` Field

Every MCP Description document MUST include a `mcpdesc` property at the root level. This property declares which version of this specification the document conforms to.

```json
{
  "mcpdesc": "0.7.0"
}
```

### 4.2 Version Format

The `mcpdesc` value MUST be a string matching a published version of this specification. The current version is `"0.7.0"`.

The specification uses [Semantic Versioning](https://semver.org/) for its own version numbers:

* **Major** version changes indicate breaking changes to the document structure
* **Minor** version changes add new optional features in a backward-compatible manner
* **Patch** version changes address errata or clarifications without structural changes

### 4.3 Version Compatibility

Implementations SHOULD support the latest specification version. Implementations MAY support multiple versions.

When processing a document, implementations MUST check the `mcpdesc` value and:

* Accept documents with a recognized `mcpdesc` version
* Reject documents with an unrecognized `mcpdesc` version or provide a clear warning

### 4.4 Forward Compatibility

Implementations SHOULD ignore unknown properties within known objects. This allows documents authored against a newer minor version to be partially processed by implementations supporting an older minor version of the same major version.

### 4.5 Relationship to MCP Protocol Versions

The `mcpdesc` version is independent of the MCP protocol version. The MCP protocol version implemented by a server is declared in `info.protocolVersion`.

A single MCP Description specification version MAY support documents describing servers implementing different MCP protocol versions.