EVI 3 and EVI 4-mini are the currently supported versions of Hume’s Empathic Voice Interface. EVI 1 and EVI 2 reached end of support on August 30, 2025. This guide explains how to set the EVI version in Chat and provides a migration path for integrations using EVI 1 or EVI 2.

## How EVI version is applied

The EVI version is resolved from the Config you use to start a Chat.

- Provide a `config_id` when you start the Chat.
- The service loads that Config and reads its evi_version.
- The Chat uses that version for its lifetime.

If you omit `config_id`, the Chat uses EVI 3 by default.

## Set the EVI version

The EVI version is set using the `evi_version` field in your [Config](https://dev.hume.ai/docs/speech-to-speech-evi/configuration/build-a-configuration). The version associated with the `config_id` you provide when starting a Chat determines which EVI version is used.

## Update an existing Config

**To change the version of an existing Config:**

1. Go to the [Configurations page](https://app.hume.ai/evi/configs).
2. Find your Config by name and click **Edit**.
3. Select a different version from the edit page.

**You can also update the version directly in the EVI playground** by selecting a Config and changing the version in the panel on the right.

[API Reference  
See our API reference for how to **update an EVI Config through the API.**](https://dev.hume.ai/reference/speech-to-speech-evi/configs/create-config-version)

## EVI 4-mini guide

### Changes

1. **EVI 4-mini is multilingual**  
   - **Impact**: EVI 4-mini supports the following languages: English, Japanese, Korean, Spanish, French, Portuguese, Italian, German, Russian, Hindi, Arabic.
   - **Action**: [Create a new voice](https://app.hume.ai/voices?category=my-voices) with a prompt in the language you’d like to use.
2. **Latency improvement**  
   - **Impact**: The model latency improvement is ~100ms on each response.

This section details the changes required to migrate from EVI 3 to EVI 4-mini. If you are migrating from EVI 1 or 2, please refer to the section below first.

### Upgrade instructions

If you’d like to migrate to EVI 4-mini:

- Set the `evi_version` field in your Config to `"4-mini"`.
- Follow the steps in [Update an existing Config](https://dev.hume.ai/docs/speech-to-speech-evi/configuration/evi-version#update-an-existing-config) to apply the change.

#### Summary

| Feature                     | EVI 3                                                 | EVI 4-mini                                               |
|-----------------------------|------------------------------------------------------|---------------------------------------------------------|
| Languages supported          | English                                              | English, Japanese, Korean, Spanish, French, Portuguese, Italian, German, Russian, Hindi, Arabic |
| Quick responses              | Available                                            | Unavailable                                             |
| Supplemental LLM            | Optional                                            | Required                                                |

## Migrating to EVI 3

###### Instructions on migrating from EVI 1 or 2

This section details the changes required to migrate from EVI 1 or 2 to EVI 3, including Config updates, SDK upgrades, and client-side message handling.

### Upgrade instructions

To upgrade to EVI 3:

- Set the `evi_version` field in your Config to `"3"`.
- Follow the steps in [Update an existing Config](https://dev.hume.ai/docs/speech-to-speech-evi/configuration/evi-version#update-an-existing-config) to apply the change.

### SDK compatibility

The following are the minimum SDK versions compatible with EVI 3. If you’re using an older version, update it using the commands below.

The versions below are minimums. For the newest EVI 3 features, performance improvements, and security fixes, upgrade to the latest SDK releases. If you run into issues, update to the latest version before troubleshooting.

[React SDK](https://www.npmjs.com/package/@humeai/voice-react) (`v0.2.1`)

```bash
npm i @humeai/voice-react@0.2.1
```

[TypeScript SDK](https://www.npmjs.com/package/hume) (`v0.12.1`)

```bash
npm install hume@0.12.1
```

[Python SDK](https://pypi.org/project/hume/) (`v0.10.1`)

```bash
uv add hume==0.10.1
```

### Breaking changes

1. **EVI 3 introduces a new voice system**
   - **Impact**: Voice options from EVI 1 and 2 are not compatible with EVI 3.
   - **Reason**: EVI 3 is powered by a speech-language model that supports an expanded, high-quality set of voices.
   - **Action**: Use a voice from the [Voice Library](https://app.hume.ai/voices) or your [Custom voices](https://app.hume.ai/voices?category=my-voices).
2. **Voice selection is now required**  
   - **Impact**: Configs that do not specify a voice must now include one.
   - **Reason**: There is no default voice for EVI 3.
   - **Action**: If your Config does not already specify a voice, update it to include one from the supported options. Our voice library includes EVI 3 clones of the popular ITO and KORA voices from EVI 1 and 2.

| Voice      | ID                                     |
|------------|---------------------------------------|
| [Ito](https://app.hume.ai/voices?q=Ito)   | `f60ecf9e-ff1e-4bae-9206-dba7c653a69e` |
| [Kora](https://app.hume.ai/voices?q=Kora) | `59cfc7ab-e945-43de-ad1a-471daa379c67` |

3. **Assistant prosody is delivered separately**
   - **Impact**: Prosody scores are no longer included in `assistant_message` payloads.
   - **Reason**: In EVI 3, prosody scores are sent asynchronously in a separate [`assistant_prosody`](https://dev.hume.ai/reference/speech-to-speech-evi/chat#receive.AssistantProsody) message. This allows for lower latency during speech synthesis.
   - **Action**: Use the shared `id` field to associate each `assistant_prosody` message with its corresponding `assistant_message`.

Assistant Message

```json
{
  "type": "assistant_message",
  "id": "c90ab17c1b064aec99c753bc172e7a3c",
  "message": {
      "role": "assistant",
      "content": "Hi! How are you today?"
  },
  "from_text": false
}
```

Assistant Prosody Message

```json
{
  "type": "assistant_prosody",
  "id": "c90ab17c1b064aec99c753bc172e7a3c",
  "models": {
    "prosody": {
      "scores": {
        "Admiration": 0.10722749680280685,
        "Adoration": 0.06395940482616425
        // ...etc.
      }
    }
  }
}
```

#### Summary

| Feature                    | EVI 1 & 2                        | EVI 3                       |
|----------------------------|----------------------------------|-----------------------------|
| Voice options              | Legacy voices                    | Voice Library or Custom voices |
| Voice selection            | Optional                         | Required                    |
| Assistant prosody          | Delivered in `assistant_message` | Delivered in `assistant_prosody` |