> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nuvion.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Versioning

> How Nuvion API versions work and how to migrate between them.

The Nuvion API is versioned by date. Breaking changes are introduced in new versions — older versions continue to work until they are deprecated.

## Setting the version

Pass the version as a request header:

```bash theme={null}
X-API-Version: 2026-02-06
```

If you omit the header, your requests are routed to the **latest version** (`2026-02-06`). To pin your integration to a specific version, always send the header explicitly.

<Tip>
  Pin to a specific version in production. Relying on the default means your integration will automatically receive future breaking changes.
</Tip>

***

## Versions

### `2026-02-06` — Current

The latest version. This is the default when no `X-API-Version` header is sent.

```bash theme={null}
X-API-Version: 2026-02-06
```

### `2026-01-01` — Previous

The previous stable version. Still supported — pass the header to continue receiving the old response structure.

```bash theme={null}
X-API-Version: 2026-01-01
```

<Note>
  A deprecation and sunset date for `2026-01-01` will be communicated with a minimum of 90 days notice via email and in these docs.
</Note>

***

## Migrating from `2026-01-01` to `2026-02-06`

To migrate, update your integration to handle the new response structure, then switch the header (or remove it to use the default).

If you need help identifying what changed for a specific endpoint, contact support.

***

## Version errors

| Error code                             | HTTP status | Description                                                                  |
| -------------------------------------- | ----------- | ---------------------------------------------------------------------------- |
| `error_auth_api_version_not_supported` | 400         | The version string in `X-API-Version` does not match any known version.      |
| `error_auth_api_version_not_available` | 403         | The requested version exists but is not available to your account.           |
| `error_auth_api_version_deprecated`    | 410         | The requested version has been discontinued. Migrate to a supported version. |
| `error_auth_api_version_locked`        | 403         | Your account is locked to a specific version. Contact support to change it.  |
| `error_auth_api_version_access_denied` | 403         | Your account does not have access to the requested version.                  |