Changes to <Dial> behavior for Enhanced Programmable SIP Feature Accounts

We are changing the behavior of <Dial> for accounts which have enabled Enhanced Programmable SIP Features. This could represent a breaking change for some call flows. If your account has not enabled Enhanced Programmable SIP Features, this does not represent a change.

The changes are:

• If a <Dial> action url is specified, Twilio will make a request to the provided action callback when the parent call is transferred to a new TwiML via call modification. Twilio will not execute any TwiML returned by the action URL since processing of the call has been transferred to the new TwiML.
• If no <Dial> action url is specified, the parent call will continue to the next verb in the current TwiML document when the parent call is modified to use new TwiML. Note: in most cases the verb after the <Dial> will not be executed since the call has been modified, but if the next verb is <Redirect> Twilio will make a request to the provided URL.

This change brings Enhanced Programmable SIP Feature enabled accounts behavior in alignment with the behavior of TwiML for non-enabled accounts.

For more information about Enhanced Programmable SIP features, see our blog post and the TwiML changelog.