Can client IP address be obtained from Arduino Ethernet2 library for W5500 during client.connected() call? I've found posts explaining how to get client IP by modifying the W5100 Ethernet library and the Adafruit CC3000 library but not the Ethernet2 lib for W5500 chip, which is different enough that the W5100 mod won't work. I suspect the TCP Socket struct will contain it, but haven't been able to find its declaration anywhere to confirm this so I can modify the library to make it accessible.
Use the new update of the 'old' Ethernet library. It is version 2.00 and you can install or update it in the Library Manager in IDE. Note, it is not Ethernet2 library. The new Ethernet library supports W5500 and has client.remoteIP().

example 

  if (client.connect(server, 80)) {
    Serial.print("connected to ");
    Serial.println(client.remoteIP());





  New features in version 2.0.0
  Auto-detection of W5100, W5200, and W5500 Ethernet hardware.