Wi-Fi Devices (P2, Photon 2, Argon, P1, Photon):

The WiFi class is available on the P2, Photon 2, Argon, Photon, and P1.

The WiFi class is not available on cellular devices such as the Boron and B-Series SoM (Gen 3) or Electron and E-Series (Gen 2).

While the Tracker SoM has a Wi-Fi module for geolocation, it cannot be used for network connectivity and thus it does not have the WiFi class.