VMS Help TCPIP Services, Programming Interfaces, RPC Server Routines, svcerr_progvers, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Called when the desired version of a program is not registered
    with the ONC RPC package. Generally, the Portmapper informs
    the client when a requested program version is not registered.
    Therefore, service implementors usually do not use this routine.