In Homie for ESP8266 v1.x, SSL was possible but it was not reliable. Due to the asynchronous nature of the v2.x, SSL is not available anymore.
This is a known esp8266/Arduino issue that polling
analogRead() too frequently forces the Wi-Fi to disconnect. As a workaround, don't poll the ADC more than one time every 3ms.
If you encouter any issues with the Wi-Fi, try changing the flash size build parameter, or try to erase the flash. See #158 for more information.