This will not work with Arduino IDE 1.6.5 (or below) or with non ESP32-S2/S3 devices (e.g. Arduino UNO, Arduino MEGA, etc.). To use this library you need to have Arduino core for the ESP32 installed.
This code may be useful to paruse for ideas or or for adapting to your own ESP32 hardware project. Over-the-air WiFi firmware updates are supported. It is for a custom PCB I ordered using EasyEDA upon ...