diff --git a/messenger.rst b/messenger.rst
index cbd286a2f50..1e5c0945e27 100644
--- a/messenger.rst
+++ b/messenger.rst
@@ -2960,12 +2960,10 @@ Let's say you want to create a message decoder::
     {
         public function decode(array $encodedEnvelope): Envelope
         {
-            $envelope = \json_decode($encodedEnvelope, true);
-
             try {
                 // parse the data you received with your custom fields
-                $data = $envelope['data'];
-                $data['token'] = $envelope['token'];
+                $data = json_decode($encodedEnvelope['body'], true);
+                $data['token'] = $encodedEnvelope['token'];
 
                 // other operations like getting information from stamps
             } catch (\Throwable $throwable) {