XTHREAD [DBINIT|THREAD]

    The XTHREAD command is used to retrieve threading information
    in format of originally created for use by the TRN[6] news
    reader.

    The command XTHREAD DBINIT may be issued prior to entering
    any groups to see if a thread database exists.  If it does,
    the database's byte order and version number are returned
    as binary data.

    If no parameter is given, XTHREAD THREAD is assumed.

    To use XTHREAD THREAD, a news group must have been selected
    earlier, else a 412 error response is returned.

    A 502 response will be returned if the client only has
    permission to transfer articles. A 503 response is returned
    if the threading files are not available.

    The format of the trn-style thread format is discussed in
    the documentation for the TRN newsreader. Since more recent
    versions of TRN support the news overview (NOV) format, it
    is recommended that this extension become historic and no
    longer be used in current servers or future implementations.

2.12.1 Responses

        288 Binary data to follow
        412 No newsgroup current selected
        502 No permission
        503 program error, function not performed