> For the complete documentation index, see [llms.txt](https://docs.ativo.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ativo.io/rest-api/api-version.md).

# API Version

## REST API version

The REST API is at **version 1** (the `/1/` in every path).

## Data model version

The data model, that is the JSON structure of the responses, is at **version 9**. Every response carries it in a header:

```http
X-API-Model-Version: 9
```

Scripts can also ask for it explicitly:

```http
GET <base URL>/meta/model/version
```

```json
{"version": 9}
```

Any script using the API should check the model version and stop, or warn, when it changes.

* **Non-breaking changes** add fields or objects and do not change the version.
* **Breaking changes** rename or remove fields or change a field's format. They increase the version.

## Data model version history

### Version 7

First version used in the API.

### Version 9

* Added `isArchived` flag on Teams, Programs and Periods.
* Teams are now either configured with a Jira board or in a custom way. When configured as a Jira board, only the Jira board id is provided. When configured as a custom team, the Jira or manual project filter is saved, as well as the mode (scrum or kanban) and estimation setting.

Version numbers can have gaps. E.g. model version 8 changes were not affecting the API.