Looking for feedback from others who have been using the SIM53xx series modules for IoT solutions over the 3G network. I have an MQTT broker on the internet to collect data for a fleet tracking system being developed. There is a lot of information about this type of solution with 2G connections but as 2G is being phased out I don't have choice but use 3G as the newer NB1 / CAT M1, sigfox etc. solutions aren't available on the small Pacific island this solution is targeted to and LoRa doesn't have sufficient range (the island isn't that small!).
After a lot of research it seems the SIM5320 is the most applicable solution (reasonable cost, popular, small, has GPS features) and there is also a whitepaper that states extensions to the AT command set has extensions for MQTT session setup, pub/sub etc. Perfect for my application, however it is only referred to in an isolated whitepaper simcom mqtt 3g and there is no other references to it in other simcom documentation or on the net.
Before I go out and purchase a couple for testing, can anyone confirm if the MQTT extensions actually exist and if they are reliable?
Also any feedback on reliability / support for simcom modules would be appreciated as I'm new to IoT over 3G.