> This is a page from the ElevenLabs documentation. For a complete page index, fetch https://elevenlabs.io/docs/llms.txt. For the full documentation in a single file, fetch https://elevenlabs.io/docs/llms-full.txt.

### Text to Speech

- **Eleven v3 (alpha)**: Released Eleven v3 (alpha), our most expressive Text to Speech model, as a research preview.

### Agents Platform

- **Custom voice settings in multi-voice**: Added support for configuring individual [voice settings per supported voice](/docs/eleven-agents/customization/voice/multi-voice-support) in multi-voice agents, allowing fine-tuned control over stability, speed, similarity boost, and streaming latency for each voice.
- **Silent transfer to human in Twilio**: Added backend configuration support for silent (cold) [transfer to number](/docs/eleven-agents/customization/tools/system-tools/transfer-to-number) in the Twilio native integration, enabling seamless handoff without announcing the transfer to callers.
- **Batch calling retry and cancel**: Added support for retrying outbound calls to phone numbers that did not respond during a [batch call](/docs/eleven-agents/phone-numbers/batch-calls), along with the ability to cancel ongoing batch operations for better campaign management.
- **LLM pinning**: Added support for [versioned LLM models with explicit checkpoint identifiers](/docs/api-reference/agents/create#request.body.conversation_config.agent.prompt.llm)
- **Custom LLM headers**: Added support for passing [custom headers to custom LLMs](/docs/api-reference/agents/create#request.body.conversation_config.agent.prompt.custom_llm.request_headers)
- **Fixed issue in non-latin languages**: Fixed an issue causing some conversations in non latin alphabet languages to fail.

### SDKs

- **Python SDK v2.3.0**: Released [Python SDK v2.3.0](https://github.com/elevenlabs/elevenlabs-python/releases/tag/v2.3.0)
- **JavaScript SDK v2.2.0**: Released [JavaScript SDK v2.2.0](https://github.com/elevenlabs/elevenlabs-js/releases/tag/v2.2.0)

### API

<Accordion title="View API changes">

## New Endpoints

### Agents Platform

- **Batch Calling**:

  - [Cancel batch call](/docs/api-reference/batch-calling/cancel) - Cancel a running batch call and set all recipients to cancelled status
  - [Retry batch call](/docs/api-reference/batch-calling/retry) - Retry a batch call by setting completed recipients back to pending status

- **Knowledge Base RAG**:
  - [Get document RAG indexes](/docs/api-reference/knowledge-base/get-rag-index) - Get information about all RAG indexes of a knowledge base document
  - [Delete document RAG index](/docs/api-reference/knowledge-base/delete-rag-index) - Delete a specific RAG index for a knowledge base document
  - [RAG index overview](/docs/api-reference/knowledge-base/rag-index-overview) - Get total size and information of RAG indexes used by knowledge base documents

## Updated Endpoints

### Agents Platform

- **Supported Voices**:

  - [Agent configuration](/docs/api-reference/agents/update#request.body.tts.supported_voices) - Added `optimize_streaming_latency`, `stability`, `speed`, and `similarity_boost` parameters for per-voice TTS customization

- **Transfer to Number**:

  - [Agent configuration](/docs/api-reference/agents/update#request.body.system_tools.transfer_to_number) - Added `enable_client_message` parameter to control whether a message is played to the client during transfer

- **Knowledge Base**:

  - Knowledge base documents now use `supported_usages` instead of `prompt_injectable` for better usage mode control
  - RAG index creation now returns enhanced response model with usage information

- **Custom LLM**:

  - [Agent configuration](/docs/api-reference/agents/update#request.body.llm.custom_llm) - Added `request_headers` parameter for custom header configuration

- **Widget Configuration**:

  - [Agent platform settings](/docs/api-reference/agents/update#request.body.platform_settings.widget_config) - Added comprehensive `styles` configuration for widget appearance customization

- **LLM**:

  - Added support for [versioned LLM models](/docs/api-reference/agents/create#request.body.conversation_config.agent.prompt.llm) with explicit version identifiers

</Accordion>

> ElevenLabs provides APIs and SDKs for text to speech, voice cloning, speech to text, sound effects, voice isolator, voice changer, and conversational AI agents. Build voice-enabled applications with lifelike audio generation.