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Changes to message delivery callbacks and DLR wait time

What's happening?

Effective July 6, 2026, Bandwidth is introducing a new message-sent callback and announcing the retirement of the current message-sending callback on January 6, 2027. We’re also extending the Delivery Receipt (DLR) wait time from 2 hours to 73 hours. These changes are designed to improve message delivery reporting and provide clearer visibility across messaging channels.

What do I need to know?

The changes are summarized below:

Change

Description

Introducing the message-sent callback

The message-sent event triggers when Bandwidth confirms the handoff of your message downstream. It indicates receipt at the transport level, however it does not confirm that the carrier has processed or accepted the message for delivery to the handset. Use this signal to:

  • Confirm a message has cleared Bandwidth’s validation and routing.

  • Track end-to-end delivery latency from your platform to Bandwidth, and from Bandwidth to the carrier.

  • Reconcile your outbound queue against actual handoffs off our network.

Retiring the message-

sending callback

The current MMS receipt message-sending callback has been deprecated and will be fully decommissioned on January 6th, six months after this notification. This doesn't affect any other existing callbacks, and they will continue to behave as they do today.

Extending the DLR wait time from 2 hours to 73 hours

Extended DLR wait time will allow us to process the late delivery receipts we receive from the industry. As a result, you may receive message-delivered and message-failed webhooks for up to 73 hours after sending a message, instead of the current 2-hour window. By allowing more time for DLRs to be received, we expect the number of 902 webhooks to decrease, as fewer messages will expire before a final delivery status is received.

What do I need to do?

  • Confirm your webhook endpoints can accept the message-sent callback without rejection and ensure they will no longer process the message-sending callback on January 6, 2027.

  • If your webhook endpoints can accept the message-sent callback, enable it on each relevant Application separately in the Bandwidth App. For high-volume Applications, please reach out to your Customer Success Manager to validate endpoint readiness and coordinate rollout timing.

  • For payload examples, event-ordering scenarios, and step-by-step opt-in instructions, see our developer docs.

Questions?

Reach out to your Bandwidth Support Team!

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