VMS Help V73 Features, System Management Features, ARB SUPPORT Qualifier Added to INSTALL Utility  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Beginning with OpenVMS Alpha Version 7.3, you can use the /ARB_
    SUPPORT qualifier with the ADD, CREATE, and REPLACE commands in
    the INSTALL utility. The ARB_SUPPORT qualifier provides Access
    Rights Block (ARB) support to products that have not yet been
    updated the per-thread security Persona Security Block (PSB) data
    structure.

    This new qualifier is included in the INSTALL utility
    documentation in the OpenVMS System Management Utilities
    Reference Manual.