1.I am using SIM808 module with esp32. It's working fine with normal MQTT over TCP. But it's not working while implementing secured MQTT. 2. I am sending thin command (AT+SSLSETROOT="C:\USER\HENRY_SSL.CRT") for set the root certificate(referred this document"SIM800 Series_MQTT_Application Note_V1.03"), the response I'm getting from gsm "+CME ERROR: unknown". 3. If I'm using this command (AT+SMSSL=1), same error I'm getting. I checked with HTTP commands it's working fine, But AT+HTTPSSL=1 command not working. The sim808 not responding SSL related commands.
But as per the simcom website sim808 supports SSL. Is I need to upgrade any firmware?