WeatherCat Version 4.0.0 dev release #13 is now available for testing. See https://athena.trixology.com/index.php?topic=3713.0 for more details and download.
WimI don't know for sure, but I believe CGI uploading has not changed from the manual. I don't use it but Stu did a pretty thorough edit of the manual for WC 3.0 and he didn't change the CGI section.