/VERSION_LIMIT[=n]

    Sets the maximum number of versions that a specified file can
    have in a directory. If you do not set a version limit, a value
    of 0 is used, indicating that the number of file versions is
    limited only to the Files-11 architectural limit of 32,767.
    When creating a file, if the total number of versions of that
    file name exceeds the specified version limit, then the file
    with the lowest version number is deleted from the directory
    without notification to the user.

    If you set the version limit to 3 when there are already five
    versions of that file in a directory, there will continue to be
    five versions of that file unless you specifically delete some
    or purge the directory. Once the number of file versions is
    equal to or less than the current version limit, this version
    limit is maintained.

    The version limit applies to all existing versions of a
    specified file in a directory regardless of whether or not
    you specified any version in the command.

    To view the version limit on a file, use the DIRECTORY/FULL
    command on a file name and look at the File Attributes field
    of the output or use the F$FILE_ATTRIBUTES(filename,"VERLIMIT")
    lexical function.