We're on IMIS 20.1. From a classic ASP (!) page, I'm replacing the old IBO-calling logic with calling ATS's web services, in this case to insert a contact address (IMIS's Name_Address table). It's the insertContactAddress() method.
I went to ATS's ASMX page to test this method to make sure I'm on the right track... clicked on the method, typed in the address values, and clicked Invoke.