diff --git a/src/PhpWord/Shared/ZipArchive.php b/src/PhpWord/Shared/ZipArchive.php
index bc71e74b..6517ca8a 100644
--- a/src/PhpWord/Shared/ZipArchive.php
+++ b/src/PhpWord/Shared/ZipArchive.php
@@ -133,6 +133,13 @@ class ZipArchive
 
         if (!$this->usePclzip) {
             $zip = new \ZipArchive();
+
+            // PHP 8.1 compat - passing null as second arg to \ZipArchive::open() is deprecated
+            // passing 0 achieves the same behaviour
+            if ($flags === null) {
+                $flags = 0;
+            }
+
             $result = $zip->open($this->filename, $flags);
 
             // Scrutizer will report the property numFiles does not exist