# invalid_api_version

> The Tickwire-Version header, or the apiVersion to pin, names no published API version.

Source: https://tickwire.io/docs/errors/invalid_api_version/

HTTP 400. Nothing reached the broker.

**Likely causes:**

- The value is not a date in YYYY-MM-DD form.
- The date is not one of the published versions (the message and metadata.supportedVersions list them).

**What to do:** Send a published version from the versioning page, or omit the header to use your organisation's pinned version. Nothing was sent or changed.

**Retry:** No. The same request gets the same answer; change something first.

Listed under [Requests and validation](https://tickwire.io/docs/errors/#requests-and-validation) in [Errors](https://tickwire.io/docs/errors/). Send the error's `requestId` to support and we can find the request.