+ <lastBuildDate><?php echo mysql2date('r', get_lastcommentmodified('GMT')); ?></lastBuildDate>
+ <sy:updatePeriod><?php echo apply_filters( 'rss_update_period', 'hourly' ); ?></sy:updatePeriod>
+ <sy:updateFrequency><?php echo apply_filters( 'rss_update_frequency', '1' ); ?></sy:updateFrequency>