diff --git a/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/directorytree/ldaprecord/src/Configuration/Validators/StringOrNullValidator.php b/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/directorytree/ldaprecord/src/Configuration/Validators/StringOrNullValidator.php
new file mode 100644
index 0000000..bc23372
--- /dev/null
+++ b/mailcow/src/mailcow-dockerized/data/web/inc/lib/vendor/directorytree/ldaprecord/src/Configuration/Validators/StringOrNullValidator.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace LdapRecord\Configuration\Validators;
+
+class StringOrNullValidator extends Validator
+{
+    /**
+     * The validation exception message.
+     *
+     * @var string
+     */
+    protected $message = 'Option [:option] must be a string or null.';
+
+    /**
+     * @inheritdoc
+     */
+    public function passes()
+    {
+        return is_string($this->value) || is_null($this->value);
+    }
+}