Commune

400invalid_version

Unsupported contract version

The `Commune-Version` header names a contract version this API does not serve. Send one from `allowed_values`, or leave the header out.

The API is versioned by the Commune-Version request header, not by the URL. This error means the header was present and its value is not a version the API currently serves. allowed_values lists every version it does serve, and param is Commune-Version.

A version is an opaque string. Today every published version looks like a date, but the API compares the value for exact equality and never parses it, so 2026-8-26 or a date with a time attached is simply an unknown version.

It is a 400 like bad_request, and has its own code because nothing in the body or the query string will fix it. If the header is left out, the request is served the version your API key was issued against, so an integration is never moved to a new contract without asking for it. An empty header counts as absent. See pinning the contract version.

The version is checked after the credential, so a request with both a bad credential and a bad version reports unauthorized first.

Why it happens, and how to fix it

  1. A typo or a different format

    The value is close to a real version but not equal to it: a missing leading zero, surrounding quotes, a trailing time or time zone, or a different separator.

    Fix: Copy a value from allowed_values exactly. GET /status reports the newest version as version, and every response echoes the version that served it in its own Commune-Version header.

  2. A version that is not released, or no longer served

    The value names a contract that does not exist yet (for example today's date, guessed rather than looked up), or an old one that has been retired.

    Fix: Send one of allowed_values, normally the newest. If you are moving off a retired version, read the API changelog first, since the shapes you depend on may have changed.

  3. A header meant for something else

    The header was set by a client library or a copied snippet with a value from another API or another setting, for example a library version number.

    Fix: Set Commune-Version explicitly to one of allowed_values wherever you build requests, or remove whatever sets it and let the key's pinned version apply.

Retrying

No: send the request again with a value from allowed_values, or without the header.

Headers

  • Commune-Version

    The version this error response was served under: the newest one, since the one you asked for does not exist.

Example response

HTTP 400
{
  "error": {
    "code": "invalid_version",
    "message": "Unsupported value \"2026-09-01\" for the Commune-Version header. Supported versions: 2026-08-26. Omit the header to use the version your key was issued against.",
    "param": "Commune-Version",
    "allowed_values": [
      "2026-08-26"
    ],
    "request_id": "req_01j9c8h1q7m3n4p5r6s7t8u9v0",
    "docs_url": "https://usecommune.dev/errors/invalid_version"
  }
}

Often confused with bad_request.