# unsupported_api_version

> Unknown Guv-Version. The Guv-Version header names a version Guv does not know.

**Unknown Guv-Version.** The `Guv-Version` header names a version Guv does not know. Versions are dates, such as `2026-11-01`.

- **HTTP status:** `400 Bad Request`
- **CLI exit code:** `2` (the request or file is not valid)
- **Retry:** not as it is; the same request will fail the same way until the cause is fixed

## How to fix it

Use a supported Guv-Version such as {latest_version}, or omit the header.

Words in `{braces}` are filled in from the error response, which names the exact resource.

## What the response looks like

```json
{
  "type": "https://guv.dev/errors/unsupported_api_version",
  "title": "Unknown Guv-Version",
  "status": 400,
  "code": "unsupported_api_version",
  "detail": "The `Guv-Version` header names a version Guv does not know.",
  "fix": "Use a supported Guv-Version such as {latest_version}, or omit the header.",
  "docs_url": "https://guv.dev/errors/unsupported_api_version",
  "request_id": "req_01jbx2m9k7q4r8t5v6w3y0z1rq"
}
```

The `code` field is stable: match on it, not on `title` or `detail`, which may be reworded.