kernel/lib/Mail.php
public function send() : bool
	{
		$sHeaders = 'From: ' . $this->_sFrom . "\r\n";

		if (empty($this->_aAttachments)) {
			
			if ($this->_sFormat == "HTML") {
				
				$sHeaders .= 'MIME-Version: 1.0' . "\r\n";
				$sHeaders .= 'Content-type: text/html; charset=UTF-8' . "\r\n";
			}
			
			return mail(implode(',', $this->_aRecipient), $this->_sSubject, $this->_sMessage, $sHeaders);
		}
		else {

			$sBoundary = "_" . md5(uniqid(rand()));

			$sAttached = "";

			foreach ($this->_aAttachments as $aAttachment) {
				
				$sAttached_file = chunk_split(base64_encode($aAttachment["content"]));
				$sAttached = "\n\n" . "--" . $sBoundary . "\nContent-Type: application; name=\"" . $aAttachment["name"] . "\"\r\nContent-Transfer-Encoding: base64\r\nContent-Disposition: attachment; filename=\"" . $aAttachment["name"] . "\"\r\n\n" . $sAttached_file . "--" . $sBoundary . "--";
			}

			$sHeaders = 'From: ' . $this->_sFrom . "\r\n";
			$sHeaders .= "MIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=\"$sBoundary\"\r\n";

			$sBody = "--" . $sBoundary . "\nContent-Type: " . ($this->_sFormat == "HTML" ? "text/html" : "text/plain") . "; charset=UTF-8\r\n\n" . $this->_sMessage . $sAttached;

			return mail(implode(',', $this->_aRecipient), $this->_sSubject, $sBody, $sHeaders);
		}
	}
public function send() : bool
	{
		$sHeaders = 'From: ' . $this->_sFrom . "\r\n";

		if (empty($this->_aAttachments)) {
			
			if ($this->_sFormat == "HTML") {
				
				$sHeaders .= 'MIME-Version: 1.0' . "\r\n";
				$sHeaders .= 'Content-type: text/html; charset=UTF-8' . "\r\n";
			}
			
			return mail(implode(',', $this->_aRecipient), $this->_sSubject, $this->_sMessage, $sHeaders);
		}
		else {

			$sBoundary = "_" . md5(uniqid(rand()));

			$sAttached = "";

			foreach ($this->_aAttachments as $aAttachment) {
				
				$sAttached_file = chunk_split(base64_encode($aAttachment["content"]));
				$sAttached = "\n\n" . "--" . $sBoundary . "\nContent-Type: application; name=\"" . $aAttachment["name"] . "\"\r\nContent-Transfer-Encoding: base64\r\nContent-Disposition: attachment; filename=\"" . $aAttachment["name"] . "\"\r\n\n" . $sAttached_file . "--" . $sBoundary . "--";
			}

			$sHeaders = 'From: ' . $this->_sFrom . "\r\n";
			$sHeaders .= "MIME-Version: 1.0\r\nContent-Type: multipart/mixed; boundary=\"$sBoundary\"\r\n";

			$sBody = "--" . $sBoundary . "\nContent-Type: " . ($this->_sFormat == "HTML" ? "text/html" : "text/plain") . "; charset=UTF-8\r\n\n" . $this->_sMessage . $sAttached;

			return mail(implode(',', $this->_aRecipient), $this->_sSubject, $sBody, $sHeaders);
		}
	}
send the mail

@access public private
@return bool