AT+CMGR=3
+CMS ERROR: Invalid memory index
AT+CPMS="SM","SM","SM"
+CPMS: 4,25,4,25,4,25

OK
AT+CMGR=3
ERROR
AT+CMGR=2
+CMGR: "REC UNREAD","+46739544972","","17/10/18,11:11:55+08"
Hej

OK
AT+CMGR=1
+CMGR: "REC UNREAD","+46739544972","","17/10/18,11:08:55+08"
Tjena tjena.

OK
AT+CMGR=0
+CMGR: "REC UNREAD","+46722041970","","17/10/18,11:06:08+08"
Hej Alex!

OK