TinyGSM
A small Arduino library for GSM modules, that just works
..., ...) All modules support TCP connections. Most modules support multiple simultaneous connections. TCP and SSL connections can usually be mixed up to the total number of possible connections. Many GSM modems, WiFi, and radio modules can be controlled by sending AT commands over Serial. TinyGSM knows which commands to send, and how to handle AT responses, and wraps that into the standard Arduino Client interface.