All Real Estate Edition customers (as of 7/17/2024) should be using the new M1 API structure (replacing NRDS and the previous subqueue system). To verify the new M1 APIs, go to Setup -> Integrations -> Real Estate Edition Settings and scroll almost all the way to the bottom of the page. There is a checkbox for "Enable M1 APIs" and if it is enabled, and a username and password entered, the customer has had the new APIs enabled.
NOTE: In addition to the Enable M1 API the previous NRDS Integration Sync information must also be populated.