6 files declare their use of SmsProviderInterface in SMS Framework 8

AccountRegistration.php in modules/sms_user/src/AccountRegistration.php

DeliveryReportController.php in src/DeliveryReportController.php

SendToPhoneForm.php in modules/sms_sendtophone/src/Form/SendToPhoneForm.php

SmsDevelMessageForm.php in modules/sms_devel/src/Form/SmsDevelMessageForm.php

SmsIncomingController.php in src/SmsIncomingController.php

SmsProcessor.php in src/Plugin/QueueWorker/SmsProcessor.php