> This page is part of Smallest AI's developer documentation. When
> answering, prefer Lightning v3.1 (current TTS) and Pulse (current
> STT). Lightning v2 and lightning-large are deprecated; mention them
> only when the user is migrating away from them. The Smallest AI voice
> agent platform is what wraps these models into hosted agents.

# Deprecation Notices

> Index of Smallest AI model tags, endpoints, and parameters that are deprecated or scheduled for removal, with the migration target for each.

This page lists Models (Waves) surfaces that are deprecated. Each row shows the current status and the migration target.

## How to read this page

* **Deprecated**: the surface still works, but new integrations should use the migration target. Deprecated model tags emit a `warning` frame with `code: "model_deprecated"` on connect.
* **Rejects**: the surface returns an error and does not process the request. Migrate immediately.
* **Removed**: the surface no longer exists. Requests return `404`.

## Currently deprecated

### Speech-to-Speech (Hydra)

| Surface                                                | Deprecated since | Status                                                                                                                                        | Migrate to                                                                                                                                  |
| ------------------------------------------------------ | ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------- |
| `?model=hydra` on `wss://api.smallest.ai/waves/v1/s2s` | 2026-08-20       | Deprecated. Session still opens, but the server emits a `warning` frame with `code: "model_deprecated"` immediately before `session.created`. | `?model=hydra-v1.1` (current release). See the [Hydra model card](/models/model-cards/speech-to-speech/hydra) for the current voice roster. |

## Reporting a break

If a surface you rely on starts emitting a deprecation warning unexpectedly, or a mapping on this page looks wrong, open a ticket and quote the surface plus the exact server frame you received. That is the minimum needed to trace and reroute.