But I'd imagine the modem AT / MBIM command would just map "SMS" operations to RCS transport if that happened... since there is separation from the "API" to send/receive and the actually 3GPP communications. i.e.might be transparent to user//tool/sms (and/or just require firmware update). And it also could be just the backend SS7/MAP interchange where SMS is not allowed, and the carriers have to use RCS as inter-carrier exchange. But SMS is a problem in that it still uses the PSTN's SS7 backbone, where one can presume multiple nation states are capturing most/all SMS messages.