Retell AI API · Endpoint removal
outbound_sms_agent_id on PATCH /update-phone-number/{} stops working
Stopped working
Calls to PATCH /update-phone-number/{}, body parameter outbound_sms_agent_id on Retell AI API stopped working on March 31, 2026.
What to use instead of these calls
Send outbound_sms_agents instead: a list of {agent_id, agent_version, weight} entries whose weights sum to 1 (one agent: weight 1).
Calls it hits
PATCH /update-phone-number/{}body parameter outbound_sms_agent_id
After 03/31/2026, the deprecated single-agent fields will no longer be supported.
Facts
- API
- Retell AI API
api.retellai.com - Kind
- Endpoint removal
- Takes effect
- March 31, 2026
- Calls after that day
- Fail
- Source
- Announcement
- Last updated
More from Retell AI API
- inbound_agent_id on PATCH /update-phone-number/{} stops working Stopped working
- inbound_agent_id on POST /create-phone-number stops working Stopped working
- inbound_agent_id on POST /import-phone-number stops working Stopped working
- inbound_sms_agent_id on PATCH /update-phone-number/{} stops working Stopped working
- inbound_sms_agent_id on POST /create-phone-number stops working Stopped working
- inbound_sms_agent_id on POST /import-phone-number stops working Stopped working