I personally never worked with Mqtt but I do have a GSM module.
Plus I have no clue about how to make libraries.
I found in my experiments that different modules respond a bit differently.
My A6 module responds differently from the s800 to the same commands.
I can try to help with the GSM part for my particular module.
I guess your best bet would be one or two code modules to interact together, but it won't be easy.
I personally never worked with Mqtt but I do have a GSM module.
Plus I have no clue about how to make libraries.
I found in my experiments that different modules respond a bit differently.
My A6 module responds differently from the s800 to the same commands.
I can try to help with the GSM part for my particular module.
I guess your best bet would be one or two code modules to interact together, but it won't be easy.
MMMM..if it's different, I have the SIM800l and it works perfectly with this library.
The idea is to unite all those libraries in one, and then convert it to a B4R library
The problem is The module responses to the AT commands, depending on the implemented version by the manufacturer, they may vary, as I have encounered.
For instance, my module response to the "registered" commands differs from the one in the Code Module Erel provided to work with GSM modules.
Because of this, I went with the "create a new one yourself" route.