The RAD authentication API is significantly different in Oracle Solaris 11.4.
The authentication API moved from version 1.0 to version 2.0, which required changes to the client code that uses the API. Some of the source code changes are small, such as using a different header file, library, Python module, or Java jar file. Some changes are large, such as the authentication API now interacts with the RAD HTTP/REST APIs directly. These changes are incompatible with the Oracle Solaris 11.3 authentication API.
RAD C client bindings support only 64-bit RAD clients and modules. For more information, see the rad(8) man page.
Ensure that you use the RAD client bindings for the latest version of Python, which is Python 3.7.
The community is ending support for Python 2.7 and Python 3.5, so the RAD client bindings for these older Python versions will no longer work.