diff --git a/models/TaxGroup.php b/models/TaxGroup.php
index ca4a5d3..2bc665f 100755
--- a/models/TaxGroup.php
+++ b/models/TaxGroup.php
@@ -56,6 +56,7 @@
          * @var TaxOption[] $options
          */
         protected $customOptions = [];
+        protected $categories = [];
         
         /**
          * @inheritdoc
--
libgit2 0.21.4