function sendmail($to, $subject, $message, $from = null, $message_id = null, $send_html = false, $priority = 1, $hotmail_fix = null)
{
	global $webmaster_email, $context, $modSettings, $txt, $scripturl;

	// Use sendmail if it's set or if no SMTP server is set.
	$use_sendmail = empty($modSettings['mail_type']) || $modSettings['smtp_host'] == '';

	// Line breaks need to be \r\n only in windows or for SMTP.
	$line_break = $context['server']['is_windows'] || !$use_sendmail ? "\r\n" : "\n";

	// So far so good.
	$mail_result = true;

	// If the recipient list isn't an array, make it one.
	$to_array = is_array($to) ? $to : array($to);

	// Sadly Hotmail & Yahoomail don't support character sets properly.
	if ($hotmail_fix === null)
	{
		$hotmail_to = array();
		foreach ($to_array as $i => $to_address)
		{
			if (preg_match('~@(yahoo|hotmail)\.[a-zA-Z\.]{2,6}$~i', $to_address) === 1)
			{
				$hotmail_to[] = $to_address;
				$to_array = array_diff($to_array, array($to_address));
			}
		}

		// Call this function recursively for the hotmail addresses.
		if (!empty($hotmail_to))
			$mail_result = sendmail($hotmail_to, $subject, $message, $from, $message_id, $send_html, $priority, true);

		// The remaining addresses no longer need the fix.
		$hotmail_fix = false;

		// No other addresses left? Return instantly.
		if (empty($to_array))
			return $mail_result;
	}

	// Get rid of slashes and entities.
	$subject = un_htmlspecialchars(stripslashes($subject));
	// Make the message use the proper line breaks.
	$message = str_replace(array("\r", "\n"), array('', $line_break), stripslashes($message));

	// Make sure hotmail mails are sent as HTML so that HTML entities work.
	if ($hotmail_fix && !$send_html)
	{
		$send_html = true;
		$message = strtr($message, array($line_break => '<br />' . $line_break));
		$message = preg_replace('~(' . preg_quote($scripturl, '~') . '([?/][\w\-_%\.,\?&;=#]+)?)~', '<a href="$1">$1</a>', $message);
	}

	list (, $from_name) = mimespecialchars(addcslashes($from !== null ? $from : $context['forum_name'], '<>()\'\\"'), true, $hotmail_fix, $line_break);
	list (, $subject) = mimespecialchars($subject, true, $hotmail_fix, $line_break);

	// Construct the mail headers...
	$headers = 'From: "' . $from_name . '" <' . (empty($modSettings['mail_from']) ? $webmaster_email : $modSettings['mail_from']) . '>' . $line_break;
	$headers .= $from !== null ? 'Reply-To: <' . $from . '>' . $line_break : '';
	$headers .= 'Return-Path: ' . (empty($modSettings['mail_from']) ? $webmaster_email: $modSettings['mail_from']) . $line_break;
	$headers .= 'Date: ' . gmdate('D, d M Y H:i:s') . ' +0000' . $line_break;

	if ($message_id !== null && empty($modSettings['mail_no_message_id']))
		$headers .= 'Message-ID: <' . md5($scripturl . microtime()) . '-' . $message_id . strstr(empty($modSettings['mail_from']) ? $webmaster_email : $modSettings['mail_from'], '@') . '>' . $line_break;
	$headers .= 'X-Mailer: SMF' . $line_break;

	// pass this to the integration before we start modifying the output -- it'll make it easier later
	if (isset($modSettings['integrate_outgoing_email']) && function_exists($modSettings['integrate_outgoing_email']))
	{
		if ($modSettings['integrate_outgoing_email']($subject, $message, $headers) === false)
			return false;
	}

	// Save the original message...
	$orig_message = $message;

	// The mime boundary separates the different alternative versions.
	$mime_boundary = 'SMF-' . md5($message . time());

	// Sending HTML?  Let's plop in some basic stuff, then.
	if ($send_html)
	{
		// This should send a text message with MIME multipart/alternative stuff.
		$headers .= 'Mime-Version: 1.0' . $line_break;
		$headers .= 'Content-Type: multipart/alternative; boundary="' . $mime_boundary . '"' . $line_break;
		$headers .= 'Content-Transfer-Encoding: 7bit' . $line_break;

		$no_html_message = un_htmlspecialchars(strip_tags(strtr($orig_message, array('</title>' => $line_break))));

		// But, then, dump it and use a plain one for dinosaur clients.
		list(, $plain_message) = mimespecialchars($no_html_message, false, true, $line_break);
		$message = $plain_message . $line_break . '--' . $mime_boundary . $line_break;

		// This is the plain text version.  Even if no one sees it, we need it for spam checkers.
		list($charset, $plain_charset_message, $encoding) = mimespecialchars($no_html_message, false, false, $line_break);
		$message .= 'Content-Type: text/plain; charset=' . $charset . $line_break;
		$message .= 'Content-Transfer-Encoding: ' . $encoding . $line_break . $line_break;
		$message .= $plain_charset_message . $line_break . '--' . $mime_boundary . $line_break;

		// This is the actual HTML message, prim and proper.  If we wanted images, they could be inlined here (with multipart/related, etc.)
		list($charset, $html_message, $encoding) = mimespecialchars($orig_message, false, $hotmail_fix, $line_break);
		$message .= 'Content-Type: text/html; charset=' . $charset . $line_break;
		$message .= 'Content-Transfer-Encoding: ' . ($encoding == '' ? '7bit' : $encoding) . $line_break . $line_break;
		$message .= $html_message . $line_break . '--' . $mime_boundary . '--';
	}
	// Text is good too.
	else
	{
		// Using mime, as it allows to send a plain unencoded alternative.
		$headers .= 'Mime-Version: 1.0' . $line_break;
		$headers .= 'Content-Type: multipart/alternative; boundary="' . $mime_boundary . '"' . $line_break;
		$headers .= 'Content-Transfer-Encoding: 7bit' . $line_break;

		// Send a plain message first, for the older web clients.
		list(, $plain_message) = mimespecialchars($orig_message, false, true, $line_break);
		$message = $plain_message . $line_break . '--' . $mime_boundary . $line_break;

		// Now add an encoded message using the forum's character set.
		list ($charset, $encoded_message, $encoding) = mimespecialchars($orig_message, false, false, $line_break);
		$message .= 'Content-Type: text/plain; charset=' . $charset . $line_break;
		$message .= 'Content-Transfer-Encoding: ' . $encoding . $line_break . $line_break;
		$message .= $encoded_message . $line_break . '--' . $mime_boundary . '--';
	}

	// SMTP or sendmail?
	if ($use_sendmail)
	{
		$subject = strtr($subject, array("\r" => '', "\n" => ''));
		if (!empty($modSettings['mail_strip_carriage']))
		{
			$message = strtr($message, array("\r" => ''));
			$headers = strtr($headers, array("\r" => ''));
		}

		foreach ($to_array as $to)
		{
			if (!mail(strtr($to, array("\r" => '', "\n" => '')), $subject, $message, $headers))
			{
				log_error(sprintf($txt['mail_send_unable'], $to));
				$mail_result = false;
			}

			// Wait, wait, I'm still sending here!
			@set_time_limit(300);
			if (function_exists('apache_reset_timeout'))
				apache_reset_timeout();
		}
	}
	else
		$mail_result = $mail_result && smtp_mail($to_array, $subject, $message, $send_html ? $headers : "Mime-Version: 1.0" . $line_break . $headers);

	// Everything go smoothly?
	return $mail_result;
}