The controller in question is an STM32F030K6T6, which has an ARM® 32-bit Cortex® -M0 low power core, 32 kB Flash memory and 4 kB SRAM. It interfaces an SIM808 for Internet connectivity.
The resources are quite limited regarding the memory.
Is it possible to implement MQTT on this device?
What requirements should a microcontroller match to be able to use/run MQTT?
(I am not asking about a complete protocol stack implementation.)