For our Subscribe by SMS to list functionality, we historically had ~6 shared USA numbers that could be selected when customers would enable this feature. The outbound messages generated by this traffic was considered ‘unregistered’ traffic since the shared USA numbers were not registered, dedicated to long codes.
On August 31st 2023, The Campaign Registry is enforcing that all A2P (application to person) traffic be coming from a registered 10dlc number. Any unregistered messages would be dropped by US carriers.
All customers who are using our Subscribe by SMS feature must be registered and utilize the 10 digit long code if they want to subscribe to users that have USA phone numbers.
If you plan to subscribe contacts from within the United States, make sure you have completed 10DLC registration by August 14, 2023 to avoid any lapse in SMS sending. You can register after this date, but you will not be able to send SMS to US users until the 3rd party approves the 10DLC registration.