I am sending bulk of mails from fetching in database
function sendMail($subject,$to,$cc,$message){
    $mail = new PHPMailer;
    $mail->isSMTP();               // Set mailer to use SMTP
    $mail->Host = 'myhostname';  // Specify main and backup SMTP servers
    $mail->SMTPAuth = true;
    $mail->Username = 'myusername';
    $mail->Password = 'pass';
    $mail->From = 'myaddress';
    $mail->FromName = 'Test';
    $mail->addAddress($to, '');     // Add a recipient
    $mail->addCC($cc);              // Add a recipient
    $mail->isHTML(true);                                  // Set email format to HTML
    $mail->Subject = ''.$subject;
    //$mail->AddEmbeddedImage('mail_logo.png', 'logoimg', 'mail_logo.png');
    $mail->Body    = $message;
$mail->AltBody="This is text only alternative body.";
    if(!$mail->send()){
        //echo $mail->ErrorInfo;
        return false;
    }
    else
    {
        return true;
    }
}
how to know users read the email or not as well as delivery report on mails???