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

# Deprecation Overview

> Browse upcoming and past Retell API deprecations and breaking changes by date — subscribe via RSS to get notified when new deprecation notices are posted.

This section tracks upcoming and some past deprecations across the Retell API. Click the RSS button at the top of the page to subscribe and receive notifications when new deprecations are announced.

<Update label="08/31/2026" tags={["API","Upcoming"]} rss="override_dynamic_variables on Update Call is deprecated and Update Call becomes ended-calls-only on 08/31/2026. Use the new Update Live Call API (PATCH /v2/update-live-call/{call_id}) to override dynamic variables on ongoing calls.">
  The `override_dynamic_variables` input on Update Call is deprecated, and Update Call becomes ended-calls-only. Changes you make through Update Call — including `data_storage_setting`, which previously took effect mid-call — now apply only to ended calls. Use the new [Update Live Call](/api-references/update-live-call) API to override dynamic variables or change `data_storage_setting` on ongoing calls.

  **Impacted API endpoints:**

  * [Update Call](/api-references/update-call) — field: `override_dynamic_variables`

  [Read more](/deprecation-notice/2026/08-31_update_call_ended_calls_only).
</Update>

<Update label="06/15/2026" tags={["API","Upcoming"]} rss="Legacy list endpoints and analysis prompt fields will be removed on 06/15/2026. Migrate to versioned list endpoints (v2/v3) and to post_call_analysis_data / post_chat_analysis_data system presets.">
  Legacy list endpoints and analysis prompt fields will be removed. Migrate to the versioned list endpoints (v2/v3) and to `post_call_analysis_data` / `post_chat_analysis_data` system presets.

  **Impacted API endpoints:**

  * [List Batch Tests](/api-references/list-batch-tests), [List Conversation Flow Components](/api-references/list-conversation-flow-components), [List Conversation Flows](/api-references/list-conversation-flows), [List Phone Numbers](/api-references/list-phone-numbers), [List Retell LLMs](/api-references/list-retell-llms), [List Test Case Definitions](/api-references/list-test-case-definitions), [List Test Runs](/api-references/list-test-runs), [List Calls](/api-references/list-calls), [List Chats](/api-references/list-chats) — endpoints replaced by versioned (v2/v3) equivalents
  * [Create Agent](/api-references/create-agent), [Update Agent](/api-references/update-agent), [Create Chat Agent](/api-references/create-chat-agent), [Update Chat Agent](/api-references/update-chat-agent) — fields: `analysis_summary_prompt`, `analysis_successful_prompt`, `analysis_user_sentiment_prompt`

  [Read more](/deprecation-notice/2026/06-15_legacy_list_endpoints).
</Update>

<Update label="05/25/2026" tags={["Models"]} rss="Claude and Gemini model replacements effective 5/25/2026: claude-4.0-sonnet -> claude-4.6-sonnet; gemini-2.0-flash and gemini-2.5-flash -> gemini-3.0-flash; gemini-2.0-flash-lite -> gemini-3.1-flash-lite.">
  Claude and Gemini models are being deprecated and automatically migrated to newer versions on 5/25/2026.

  [Read more](/deprecation-notice/2026/05-25_model_replacements).
</Update>

<Update label="04/18/2026" tags={["API"]} rss="tools and tool_ids on conversation nodes are deprecated. Use type: 'subagent' nodes instead. Existing conversation nodes with tools will be auto-migrated to subagent nodes on 04/18/2026.">
  The `tools` and `tool_ids` fields on `type: "conversation"` nodes are deprecated in favor of the new `subagent` node type.

  **Impacted API endpoints:**

  * [Create Conversation Flow](/api-references/create-conversation-flow), [Update Conversation Flow](/api-references/update-conversation-flow), [Get Conversation Flow](/api-references/get-conversation-flow), [List Conversation Flows](/api-references/list-conversation-flows), [Create Conversation Flow Component](/api-references/create-conversation-flow-component), [Update Conversation Flow Component](/api-references/update-conversation-flow-component), [Get Conversation Flow Component](/api-references/get-conversation-flow-component), [List Conversation Flow Components](/api-references/list-conversation-flow-components) — fields: `tools`, `tool_ids` (on `type: "conversation"` nodes)

  [Read more](/deprecation-notice/2026/04-18_conversation_node_tools).
</Update>

<Update label="04/03/2026" tags={["Models"]} rss="OpenAI Realtime and Cartesia Sonic model replacements effective 4/3/2026: gpt-4o-realtime -> gpt-realtime-1.5; gpt-4o-mini-realtime -> gpt-realtime-mini; sonic-2 and sonic-turbo -> sonic-3.">
  OpenAI Realtime and Cartesia Sonic models are being deprecated and replaced with newer versions. After 4/3/2026, the deprecated models will no longer be available.

  [Read more](/deprecation-notice/2026/04-03_model_replacements).
</Update>

<Update label="03/31/2026" tags={["API"]} rss="Phone number single-agent fields (inbound_agent_id, outbound_agent_id, inbound_sms_agent_id, outbound_sms_agent_id and their *_version siblings) are deprecated. Use the weighted *_agents lists instead.">
  The single-agent fields on phone number configuration are deprecated in favor of the weighted `*_agents` lists.

  **Impacted API endpoints:**

  * [Create Phone Number](/api-references/create-phone-number), [Import Phone Number](/api-references/import-phone-number), [Update Phone Number](/api-references/update-phone-number), [Get Phone Number](/api-references/get-phone-number), [List Phone Numbers](/api-references/list-phone-numbers) — fields: `inbound_agent_id`, `inbound_agent_version`, `outbound_agent_id`, `outbound_agent_version`, `inbound_sms_agent_id`, `inbound_sms_agent_version`, `outbound_sms_agent_id`, `outbound_sms_agent_version`

  [Read more](/deprecation-notice/2026/03-31_phone_number_agent_fields).
</Update>

<Update label="01/23/2026" tags={["API"]} rss="show_transferee_as_caller no longer toggles SIP REFER vs SIP INVITE. Use the new cold_transfer_mode parameter (sip_refer or sip_invite). show_transferee_as_caller now only controls caller ID display under sip_invite.">
  `show_transferee_as_caller` no longer toggles SIP REFER vs SIP INVITE in Cold Transfer options. Use the new `cold_transfer_mode` parameter instead; `show_transferee_as_caller` now only controls caller ID display under `sip_invite`.

  **Impacted API endpoints:**

  * [Create Retell LLM](/api-references/create-retell-llm), [Update Retell LLM](/api-references/update-retell-llm), [Create Conversation Flow](/api-references/create-conversation-flow), [Update Conversation Flow](/api-references/update-conversation-flow), [Create Conversation Flow Component](/api-references/create-conversation-flow-component), [Update Conversation Flow Component](/api-references/update-conversation-flow-component) — field: `show_transferee_as_caller`

  [Read more](/deprecation-notice/2026/01-23_cold_transfer_mode_selection).
</Update>