I upgraded my V.4 firmware to 5.01 and added WiFi. I successfully set WiFi up and can access the OpenEVSE webserver on my local net at its assigned IP or by DNS at http://openevse/. I then set up an account at http://data.openevse.com/emoncms, set the Node to 0, and entered the Emoncms read/write api key as listed in my Emoncms account.
I set up a new Device in Emoncms at Node:0 and type:OpenEVSE, which generated a different device access key. From elsewhere on this forum it seemed I needed to use the R/W key from my account page or as shown on the Devices Help page. However, the key in the Devices list is the one that works.