diff --git a/.openapi-generator/VERSION b/.openapi-generator/VERSION
index 6328c54..1b2d969 100644
--- a/.openapi-generator/VERSION
+++ b/.openapi-generator/VERSION
@@ -1 +1 @@
-7.17.0
+7.18.0
diff --git a/src/Api/PublicApi.php b/src/Api/PublicApi.php
index 3dd70a2..c196330 100644
--- a/src/Api/PublicApi.php
+++ b/src/Api/PublicApi.php
@@ -16,7 +16,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
@@ -387,7 +387,6 @@ public function checkStatusRequest(
             }
         }
 
-
         $defaultHeaders = [];
         if ($this->config->getUserAgent()) {
             $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
@@ -689,7 +688,6 @@ public function checkVatNumberRequest(
             }
         }
 
-
         $defaultHeaders = [];
         if ($this->config->getUserAgent()) {
             $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
@@ -991,7 +989,6 @@ public function checkVatTestServiceRequest(
             }
         }
 
-
         $defaultHeaders = [];
         if ($this->config->getUserAgent()) {
             $defaultHeaders['User-Agent'] = $this->config->getUserAgent();
diff --git a/src/ApiException.php b/src/ApiException.php
index a909a0f..8c92187 100644
--- a/src/ApiException.php
+++ b/src/ApiException.php
@@ -16,7 +16,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Configuration.php b/src/Configuration.php
index 2960b88..e771a8b 100644
--- a/src/Configuration.php
+++ b/src/Configuration.php
@@ -16,7 +16,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/FormDataProcessor.php b/src/FormDataProcessor.php
index 355d4fc..6d52513 100644
--- a/src/FormDataProcessor.php
+++ b/src/FormDataProcessor.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/HeaderSelector.php b/src/HeaderSelector.php
index 22bcbe7..5af5194 100644
--- a/src/HeaderSelector.php
+++ b/src/HeaderSelector.php
@@ -16,7 +16,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/CheckVatRequest.php b/src/Model/CheckVatRequest.php
index 9bb1857..d0a2e39 100644
--- a/src/Model/CheckVatRequest.php
+++ b/src/Model/CheckVatRequest.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/CheckVatResponse.php b/src/Model/CheckVatResponse.php
index a63f8cd..c751334 100644
--- a/src/Model/CheckVatResponse.php
+++ b/src/Model/CheckVatResponse.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/CommonResponse.php b/src/Model/CommonResponse.php
index 1b92e7b..aae6efb 100644
--- a/src/Model/CommonResponse.php
+++ b/src/Model/CommonResponse.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/CountryStatus.php b/src/Model/CountryStatus.php
index df7ae4c..8638d93 100644
--- a/src/Model/CountryStatus.php
+++ b/src/Model/CountryStatus.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/ErrorWrapper.php b/src/Model/ErrorWrapper.php
index 8838717..5b4320d 100644
--- a/src/Model/ErrorWrapper.php
+++ b/src/Model/ErrorWrapper.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/ModelInterface.php b/src/Model/ModelInterface.php
index 159baab..4365c34 100644
--- a/src/Model/ModelInterface.php
+++ b/src/Model/ModelInterface.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/Status.php b/src/Model/Status.php
index 2787da3..3d19176 100644
--- a/src/Model/Status.php
+++ b/src/Model/Status.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/StatusInformationResponse.php b/src/Model/StatusInformationResponse.php
index ad258cc..2d087e3 100644
--- a/src/Model/StatusInformationResponse.php
+++ b/src/Model/StatusInformationResponse.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/Model/StatusInformationResponseVow.php b/src/Model/StatusInformationResponseVow.php
index 4cc4bf3..60dd48c 100644
--- a/src/Model/StatusInformationResponseVow.php
+++ b/src/Model/StatusInformationResponseVow.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
diff --git a/src/ObjectSerializer.php b/src/ObjectSerializer.php
index 98bc6d6..9d5bd12 100644
--- a/src/ObjectSerializer.php
+++ b/src/ObjectSerializer.php
@@ -17,7 +17,7 @@
  *
  * The version of the OpenAPI document: 1.0.0
  * @generated Generated by: https://openapi-generator.tech
- * Generator version: 7.17.0
+ * Generator version: 7.18.0
  */
 
 /**
@@ -28,6 +28,7 @@
 
 namespace Cone\Vies;
 
+use BackedEnum;
 use DateTimeInterface;
 use DateTime;
 use GuzzleHttp\Psr7\Utils;
@@ -264,6 +265,11 @@ public static function toQueryValue(
                         // push key itself
                         $result[] = $prop;
                     }
+
+                    if ($v instanceof BackedEnum) {
+                        $v = $v->value;
+                    }
+
                     $result[$prop] = $v;
                 }
             }