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

# Versioning and deprecation

> What v1 promises not to break, how a change is announced, and the Deprecation and Sunset headers to watch for.

The API is versioned in the URL: every endpoint lives under
`https://api.dueflow.co/v1/`. There is one version today, and this page is the
policy for how it changes.

## What will not change within v1

A working integration against `/v1` keeps working. Within `v1` we will not:

* remove an endpoint or a response field
* add a required parameter, or make an optional one required
* narrow the set of accepted values for a parameter
* change the type or meaning of an existing field
* require a scope or role that your existing token does not already hold

Each of those is checked against the published OpenAPI description on every
change to the API, so a breaking change cannot ship by accident.

## What will change

Additions, without notice and without a version bump:

* new endpoints
* new response fields
* new optional parameters
* new scopes and new values for enumerations

So parse responses leniently and ignore fields you don't recognize. Anything
genuinely incompatible goes in a `/v2`, and `/v1` keeps answering alongside it.

## How a deprecation is announced

If an endpoint is ever retired:

1. It is marked `deprecated` in the [OpenAPI description](https://api.dueflow.co/v1/openapi.json)
   and in this reference.
2. Every response from it carries a `Deprecation: true` header, a `Sunset`
   header with the date it stops answering, and a `Link` header with
   `rel="deprecation"` pointing here.
3. The sunset is **at least 180 days** after the headers first appear.

```
Deprecation: true
Sunset: Thu, 01 Jul 2027 00:00:00 GMT
Link: <https://docs.dueflow.co/versioning>; rel="deprecation"
```

Watch for `Deprecation` in your client: it is on error responses too, so a
caller debugging a `403` or `429` sees the sunset as well. After the sunset
date the endpoint returns `404`.

## What is not covered

Rate limits, request costs and the exact wording of error `message` strings may
be tuned without notice. Error `code` values are stable; branch on those.


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