Fix for the wpMandrill WordPress plugin for blogs that send both plain text and HTML email

functions.php

<?php

// Add to functions.php and leave the “Content” box unticked in Settings > Mandrill
// Be sure to omit the opening <?php tag when copying this code

// Add paragraph breaks to plain text notifications sent by Mandrill
add_filter('mandrill_payload', 'wpmandrill_auto_add_breaks');
function wpmandrill_auto_add_breaks($message) {
	
	$html = $message['html'];

	$is_comment_notification = ( $message['tags']['automatic'][0] == 'wp_wp_notify_moderator' );
	$is_password_reset = ( $message['tags']['automatic'][0] == 'wp_retrieve_password' );
	$no_html_found = ( $html == strip_tags($html) ); 
		
	// Add line breaks and links to messages that don't appear to be HTML
	if ( $no_html_found || $is_comment_notification || $is_password_reset ) {
		$html = wpautop($html);
		$message['html'] = make_clickable($html);
	}

	return $message;
	
}