diff --git a/src/Util/Strings.php b/src/Util/Strings.php
index cd065aed12..ef7a2df061 100644
--- a/src/Util/Strings.php
+++ b/src/Util/Strings.php
@@ -68,7 +68,7 @@ class Strings
      */
     public static function escapeHtml($string)
     {
-        return htmlentities($string, ENT_QUOTES | ENT_HTML5, "UTF-8", false);
+        return htmlentities($string, ENT_QUOTES | ENT_HTML5, 'UTF-8', false);
     }
 
     /**