In the driver software only one version of each structure in the data path is supported.
To be able to support applications compiled with older version of the driver software in the future, all application must call the NT_Init function (see DN-0449) with the NTAPI_VERSION definition. In this way the driver software knows which version of the API the application has been compiled with, and is able to return the correct version of each structure.
If the version is not supported, NT_Init returns an error. But if NT_Init succeeds, the application is compatible with the loaded version of the driver software.