13299: 2010 Conference API feature requested using 2008 API

This error occurs when you request a conference feature that requires the 2010-04-01 Voice API, but the call or API request is still using the older 2008-08-01 API version. Update your conference workflow to use the current Voice API and make sure any call entry point is not starting the session with the older API version.

• Your application is making a conference-related request through the deprecated 2008-08-01 Voice API instead of the 2010-04-01 Voice API.
• A Twilio phone number handling the call is configured with apiVersion set to 2008-08-01.
• A TwiML Application handling the call is configured with apiVersion set to 2008-08-01.
• Your call flow tries to use a conference capability that is available in the 2010 Conference API while the session is still running on the older API version.

• Update your Voice API requests to use the 2010-04-01 base path for conference-related operations.
• Update the phone number apiVersion for incoming voice calls to 2010-04-01.
• Update the TwiML Application apiVersion to 2010-04-01 if your call flow starts through an Application resource.
• Review your conference workflow and remove or replace any conference feature that depends on the 2010 Conference API until the full call path has been upgraded.

• Programmable Voice API Overview
• REST API: Applications
• IncomingPhoneNumber resource