VMS Help LANCP, CONNECT, NODE, Qualifiers, /V4  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Indicates that MOP Version 4 formatted messages are to be used
    to make the connection. By default, LANCP determines the format
    by sending MOP Request ID messages to the remote node first in
    MOP Version 4 format, then in Version 3 format, repeating this
    process until a response is received or timeout occurs.

    You can specify the format:

    o  To allow connection to nodes that do not support Request ID
       messages

    o  As a means of getting around implementation problems with one
       of the formats