Subject: Re: [IMMEDIATE ACTION REQUIRED] Breaking Retell AI API change

Support Help
1

Hi Retell Support,

I received your notice regarding the deprecated Phone Number API fields. I am currently using Retell for my AI receptionist service, integrated with Make.com webhooks and Google Sheets for call logging.

To ensure our service doesn’t break, could you please clarify the following:

  1. Specific Fields: Which specific fields in our current configuration are flagged as deprecated?
  2. Migration Guide: Could you provide the specific documentation or migration guide for the new API version?
  3. Deadline: What is the exact date when the old fields will stop functioning entirely?
  4. Webhook Impact: Will this change affect webhook payloads, or only direct API calls?

We want to get this updated immediately to avoid any downtime.

Best regards,
Kindredluminous

2

Hi @kindredluminous

Here are the answers to your questions.

Deprecated Fields: The following single-agent fields are deprecated across Create/Import/Update/Get/List Phone Number APIs:

  • 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

Migration: Replace them with weighted agent lists (inbound_agents, outbound_agents, inbound_sms_agents, outbound_sms_agents). For a single agent, use a list with one entry and weight: 1. Example:

{
  "inbound_agents": [
    { "agent_id": "yourAgentId", "agent_version": 3, "weight": 1 }
  ]
}

Deadline: March 31, 2026. Existing data is auto-converted, but the old fields will no longer be supported after this date.

Webhook Impact: The deprecation notice specifically mentions the Phone Number API endpoints (Create, Import, Update, Get, List).However, if your Make.com webhooks reference any of these deprecated fields when calling those APIs, you’ll need to update those calls.

Full details are on the ( Deprecating on 03/31/2026 - Retell AI )

Thank You

1 Like
3

Thanks for the clarification. Our webhook-based integration is unaffected. We’ll use the new format if we need to update phone number configurations