WiFi.useDynamicIP, useDynamicIP

Instructs the system to connect to the network using a dynamically allocated IP address from the router.

A note on switching between static and dynamic IP. If static IP addresses have been previously configured using WiFi.setStaticIP(), they continue to be remembered by the system after calling WiFi.useDynamicIP(), and so are available for use next time WiFi.useStaticIP() is called, without needing to be reconfigured using WiFi.setStaticIP()

Static IP addressing is only available on the Photon and P1 (Gen 2). It is not available on the Argon or Ethernet (Gen 3), P2, or Photon 2.