diff -Nur message_highlight-1.0.1.ori/message_highlight.php message_highlight-1.0.1/message_highlight.php
--- message_highlight-1.0.1.ori/message_highlight.php	2020-07-16 01:56:38.000000000 -0400
+++ message_highlight-1.0.1/message_highlight.php	2024-09-13 11:27:15.693000000 -0400
@@ -49,7 +49,7 @@
    */
   function storage_init($p)
   {
-    $p['fetch_headers'] .= trim($p['fetch_headers']. ' ' . 'CC');
+    $p['fetch_headers'] = trim(($p['fetch_headers'] ?? '') . ' ' . 'CC');
     return($p);
   }