diff --git a/dictionaries/PropertyMap.php b/dictionaries/PropertyMap.php
index e0f91665df6..e5d32624416 100644
--- a/dictionaries/PropertyMap.php
+++ b/dictionaries/PropertyMap.php
@@ -256,7 +256,7 @@
         'client_info' => 'string',
         'client_version' => 'int',
         'connect_errno' => 'int',
-        'connect_error' => 'string',
+        'connect_error' => '?string',
         'errno' => 'int',
         'error' => 'string',
         'error_list' => 'array',