sindy
@SiB, I'm afraid the actual question is whether the LTE modem accepts some kind of service SMSes like mobile phones do, allowing the operator to remotely change settings without a previous preparation at the machine.
Yes, probably I not answer at real question.
When we go to foreign country, use roaming, we change ISP with saving the same phone number etc. we can receive from current ISP the NEW SETTINGS for WAP/MMS/InternetAPN/SyncML.. what is a e.g. WAP OTA I think... probably this is nature of original question.
I not know about any "backdoor via SMS for ISP".
SMS not have a way to modify our device from what i know :)
In many AT Commands books what I read I not see that way in LTE MODULE, probably for phones exist some more detailed information but I am not track that stuff.
We can receive from ISP his APN.
We even with some ISP not must setup outgoing SMSC (Short Message Service Center) to can send SMS.
In topic to change some LTE stuff by SMS we can do it at user-level by way described in documentation and my example. Incomming SMS from proper person can run internal script - this is only way I know about SMS way.
I hope this is better answer.