How to sort or list received "UNREAD" SMS messages

[flotulopex]

Hi pedja089,

Read one by one UNREAD MSG

I think, that's where I'm currently stuck - I have no idea how to achieve this (appart from using command AT+CMGR=n but this implies I have listed/sored the message's index before), reading messages one-by-one. All AT commands I know will list the SMS messages and (unfortunately) change their status from "REC UNREAD" to "REC READ" despite I didn't really read them.

I just noticed that, whenever an SMS message is received by the SIM7600E module I use, I get this through the UART interface:
+CMTI: "SM",n where "n" is the number (or index) of this SMS message.

I could store the message's index into an array an treat them on-by-one. But what if I miss one of these +CMTI information? What if my PIC is doing something else than "listening" to incoming messages?

I'm confused since I can't make sure that I wont miss any incoming message.

Since I don't see how to list unread messages one-by-one (can't find any info about this way of doing), should I go for listing all "REC UNREAD" messages and store their index in a list and parse them from now on "one-by-one"? Is this the way?