From 1f2833670291942249ae8878fd0fa39d93b866ec Mon Sep 17 00:00:00 2001
From: Hadi Nategh <hnategh@gmail.com>
Date: Thu, 4 Nov 2021 14:12:21 +0100
Subject: [PATCH] Fix stripos(): Argument #3 ($offset) must be contained in
 argument #1 ($haystack) by preventing empty html value being processed

---
 api/src/Mail/Html.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/api/src/Mail/Html.php b/api/src/Mail/Html.php
index 667b845e4f..470e871ae6 100644
--- a/api/src/Mail/Html.php
+++ b/api/src/Mail/Html.php
@@ -555,7 +555,7 @@ class Html
 			$searchFor = '<pre>';
 			$pos = stripos($html,$searchFor);
 		}
-		if ($pos === false)
+		if ($pos === false || !$html)
 		{
 			return $html;
 		}