$wpdb->query( 'DROP TABLE IF EXISTS ' . $wpdb->prefix . 'optiontypes' );
	$wpdb->query( 'DROP TABLE IF EXISTS ' . $wpdb->prefix . 'optiongroups' );
	$wpdb->query( 'DROP TABLE IF EXISTS ' . $wpdb->prefix . 'optiongroup_options' );

	// Update comments table to use comment_type.
	$wpdb->query( "UPDATE $wpdb->comments SET comment_type='trackback', comment_content = REPLACE(comment_content, '<trackback />', '') WHERE comment_content LIKE '<trackback />%'" );
	$wpdb->query( "UPDATE $wpdb->comments SET comment_type='pingback', comment_content = REPLACE(comment_content, '<pingback />', '') WHERE comment_content LIKE '<pingback />%'" );