If IDF version being used is 4.0, following changes will happen:
- tcpip_adapter will be used, instead of esp_netif.
- MQTT port 8883 will be used, even if 443 is chosen, because
443 requires ALPN options in MQTT, which aren't supported in IDF 4.0
MAC address is a public information and can also be sniffed easily. Creating the proof of
possession pin from that is not secure enough. Instead, a random stream of bytes is now generated
and stored in the fctry partition during claiming and that is used for the PoP.