EVI Version

EVI 3 is the only supported version 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. The version associated with the config_id you provide when starting a Chat determines which EVI version is used.

To select a version when creating a Config:

1. Go to the Configurations page.
2. Click Create config.
3. In the first step of the flow, choose your desired EVI version.

Update an existing Config

To change the version of an existing Config:

1. Go to the Configurations page.
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.

Migrating to EVI 3

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 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.

React SDK (v0.2.1)

1
npm i @humeai/voice-react@0.2.1

TypeScript SDK (v0.12.1)

1
npm install hume@0.12.1

Python SDK (v0.10.1)

1
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 or your Custom 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	f60ecf9e-ff1e-4bae-9206-dba7c653a69e
   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 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

   1
   {
   2
     "type": "assistant_message",
   3
     "id": "c90ab17c1b064aec99c753bc172e7a3c",
   4
     "message": {
   5
         "role": "assistant",
   6
         "content": "Hi! How are you today?"
   7
     },
   8
     "from_text": false
   9
   }

   Assistant Prosody Message

   1
   {
   2
     "type": "assistant_prosody",
   3
     "id": "c90ab17c1b064aec99c753bc172e7a3c",
   4
     "models": {
   5
       "prosody": {
   6
         "scores": {
   7
           "Admiration": 0.10722749680280685,
   8
           "Adoration": 0.06395940482616425,
   9
           // ...etc.
   10
         }
   11
       }
   12
     }
   13
   }

Summary