You should be able to reach each of the old API files the same way. So you can type the URL https://mail.smartertools.com/Services/svcUserAdmin.asmx and see the information on that API file.
The only thing that doesn't exist anymore is the old documentation page. If you are looking for the current 16 documentation for the old API you would need to go to the new documentation page, located at https://mail.smartertools.com/Documentation/api, and look at the legacy API section.
Larry Duran
Software Developer
SmarterTools Inc.
www.smartertools.com