This document appears to be ready and well written.

From a security point of view this document does not have much to review as security services related to this protocol is handled by a separate document (Security Services for the Registration Data Access Protocol (RDAP) RFC 7481).
At a first glance the security considerations sections seems a bit limited, but when taking RFC 7481 into account, which has already been approved as a reasonable set of security functions for this protocol, the security considerations section seems adequate.