h3><a name="namespace">MHonArc code under the <tt>mhonarc</tt> namespace</a></h3>
    <p>If upgrading from v2.1.x, or earlier, any custom filters you
    have developed may need to modified.  If your filter accessed
    some main variables, your filter will not operate properly.
    All variables that used to be in package "main" are no longer.
    The major variables are now in package "mhonarc".  For example,
    <tt>$::OUTDIR</tt> is now <tt>$mhonarc::OUTDIR</tt>.  See the
    <a href="resources/mimefilt