From 7fd4511a214275eddd0445b6185d9dbea814df5d Mon Sep 17 00:00:00 2001
From: Philipp <admin@philipp.info>
Date: Tue, 22 Sep 2020 22:48:34 +0200
Subject: [PATCH] Fix phpmailer (Case sensitive Check)

---
 phpmailer/phpmailer.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/phpmailer/phpmailer.php b/phpmailer/phpmailer.php
index 5b43c8f1..3f6f5f5f 100644
--- a/phpmailer/phpmailer.php
+++ b/phpmailer/phpmailer.php
@@ -92,7 +92,7 @@ function phpmailer_emailer_send_prepare(App $a, IEmail &$email)
 		if (!empty($email->getAdditionalMailHeader())) {
 			foreach ($email->getAdditionalMailHeader() as $name => $values) {
 				// Set the "Message-ID" header for PHP-Mailer directly
-				if ($name == 'Message-Id') {
+				if (strtolower($name) === 'message-id') {
 					// implode all values to one entry, because there's only one value possible
 					$mailer->MessageID = trim(implode("", $values));
 				} else {