OK, so I have it mostly working and figured I would share it in the hopes of someone who knows a bit more cleaning things up and adding anything that needs to be added.For example, in the below changes, inline attachment/images are not being included.  This should be fixed.  Everything else is working as far as I know.All changes need to be made in /include/class.mailer.phpYou can download the SendGrid PHP API from here://github.com/sendgrid/sendgrid-phpI installed it in the /include folder of osTicket.Changes to class.mailer.php:include_once(INCLUDE_DIR.'class.email.php');require_once(INCLUDE_DIR.'html2text.php');+require_once(INCLUDE_DIR.'sendgrid-php/sendgrid-php.php'-------------------------------------------------------------------------------------------------------------------------------------------        if (is_object($to) && is_callable(array($to, 'getEmail'))) {            // Add personal name if available            if (is_callable(array($to, 'getName'))) {+ $toName = sprintf('"%s"', $to->getName()->getOriginal());+ $toEmail = $to->getEmail();                $to = sprintf('"%s" <%s>',                    $to->getName()->getOriginal(), $to->getEmail()                );            }            else {+ $toName = "";+ $toEmail = $to->getEmail();                $to = $to->getEmail();            }        }-----------------------------------------------------------------------------------------------------------------------------------------------------Contiued on next post.

+ // Hard coded.  Should be an option on the mail config.+ $sendgrid = true;+ if ($sendgrid) {+ $ost->logDebug("Sending with sendgrid",$this->getFromAddress());+ + $mail = new SendGrid\Mail();+ + $from = new SendGrid\Email(preg_replace("/(\r\n|\r|\n)/s",'', trim($this->getEmail()->getName())), $this->getEmail()->getEmail());+ $mail->setFrom($from);+ + $mail->setSubject($subject);+ + if ($isHtml)+ $content = new SendGrid\Content("text/html", $message);+ else+ $content = new SendGrid\Content("text/plain", $message);+ $mail->addContent($content);+ + $personalization = new SendGrid\Personalization();+ $to = new SendGrid\Email(preg_replace("/(\r\n|\r|\n)/s",'', trim($toName)), $toEmail);+ $personalization->addTo($to);+ + foreach ($headers as $key => $value){+ $ost->logDebug($key,$value);+ if ($key != "To" && $key != "From" && $key != "Subject" && $key != "Content-Type")v $personalization->addHeader($key,$value);+ }+ $mail->addPersonalization($personalization);+

+     if(($attachments=$this->getAttachments())) {+ $ost->logDebug("Found attachments","");+ foreach($attachments as $attachment) {+ if ($attachment+ && ($file=AttachmentFile:($attachment))) {+ + $ost->logDebug("Adding attachment",$file->getData());+ + $attachment = new SendGrid\Attachment();+ $attachment->setContent(base64_encode($file->getData()));+ $attachment->setType($file->getType());+ $attachment->setFilename($file->getName());+ $attachment->setDisposition("attachment");+ $mail->addAttachment($attachment);+ + $ost->logDebug("Added attachment",$file->getName());+ + }+ }+ }+ + $apiKey = "???";+ $sg = new \SendGrid($apiKey);++ $response = $sg->client->mail()->send()->post($mail);+ + if ($response->statusCode() == 202) {+ $ost->logDebug("Sent via sendgrid","");+ return $messageId;+ }+ else {+ $ost->logError("Sent via sendgrid failed",strval($response->statusCode()));+ $ost->logError("Sent via sendgrid failed",strval($response->body()));+ return false;+ }+ }+ else {        // Cache smtp connections made during this request        static $smtp_connections = array();        if(($smtp=$this->getSMTPInfo())) { //Send via SMTP