diff --git a/snappymail/v/0.0.0/app/libraries/Sabre/Xml/Element/KeyValue.php b/snappymail/v/0.0.0/app/libraries/Sabre/Xml/Element/KeyValue.php
index 144fb3dec..cdfcd9b79 100644
--- a/snappymail/v/0.0.0/app/libraries/Sabre/Xml/Element/KeyValue.php
+++ b/snappymail/v/0.0.0/app/libraries/Sabre/Xml/Element/KeyValue.php
@@ -97,6 +97,7 @@ class KeyValue implements Xml\Element
      */
     public static function xmlDeserialize(Xml\Reader $reader): array
     {
+        require_once __DIR__ . '/../Deserializer/functions.php';
         return Deserializer\keyValue($reader);
     }
 }