diff --git a/lib/Api/PostcardsApi.php b/lib/Api/PostcardsApi.php
index b4c3df1..39ca55b 100755
--- a/lib/Api/PostcardsApi.php
+++ b/lib/Api/PostcardsApi.php
@@ -76,14 +76,15 @@ class PostcardsApi
     protected $hostIndex;
 
     /**
-     * @param Configuration   $config
-     * @param HeaderSelector  $selector
+     * @param Configuration|null   $config
+     * @param ClientInterface|null $client
+     * @param HeaderSelector|null  $selector
      * @param int             $hostIndex (Optional) host index to select the list of hosts if defined in the OpenAPI spec
      */
     public function __construct(
-        Configuration $config = null,
-        ClientInterface $client = null,
-        HeaderSelector $selector = null,
+        ?Configuration $config = null,
+        ?ClientInterface $client = null,
+        ?HeaderSelector $selector = null,
         $customHeaders = [],
         $hostIndex = 0
     ) {
diff --git a/lib/Model/AddressEditable.php b/lib/Model/AddressEditable.php
index 0fa1beb..6fb9b11 100755
--- a/lib/Model/AddressEditable.php
+++ b/lib/Model/AddressEditable.php
@@ -229,10 +229,10 @@ public function getModelName()
     /**
      * Constructor
      *
-     * @param mixed[] $data Associated array of property values
+     * @param mixed[]|null $data Associated array of property values
      *                      initializing the model
      */
-    public function __construct(array $data = null)
+    public function __construct(?array $data = null)
     {
         $this->container['address_line1'] = $data['address_line1'] ?? null;
         $this->container['address_line2'] = $data['address_line2'] ?? null;
diff --git a/lib/Model/IntlVerification.php b/lib/Model/IntlVerification.php
index d2b1f49..11efb4a 100755
--- a/lib/Model/IntlVerification.php
+++ b/lib/Model/IntlVerification.php
@@ -312,10 +312,10 @@ public function getObjectAllowableValues()
     /**
      * Constructor
      *
-     * @param mixed[] $data Associated array of property values
+     * @param mixed[]|null $data Associated array of property values
      *                      initializing the model
      */
-    public function __construct(array $data = null)
+    public function __construct(?array $data = null)
     {
         $this->container['id'] = $data['id'] ?? null;
         $this->container['recipient'] = $data['recipient'] ?? null;
diff --git a/lib/Model/Postcard.php b/lib/Model/Postcard.php
index d053c34..f3de8d1 100755
--- a/lib/Model/Postcard.php
+++ b/lib/Model/Postcard.php
@@ -310,10 +310,10 @@ public function getObjectAllowableValues()
     /**
      * Constructor
      *
-     * @param mixed[] $data Associated array of property values
+     * @param mixed[]|null $data Associated array of property values
      *                      initializing the model
      */
-    public function __construct(array $data = null)
+    public function __construct(?array $data = null)
     {
         $this->container['id'] = $data['id'] ?? null;
         $this->container['to'] = $data['to'] ?? null;
diff --git a/lib/Model/PostcardEditable.php b/lib/Model/PostcardEditable.php
index 265ebe0..4177a62 100755
--- a/lib/Model/PostcardEditable.php
+++ b/lib/Model/PostcardEditable.php
@@ -234,10 +234,10 @@ public function getModelName()
     /**
      * Constructor
      *
-     * @param mixed[] $data Associated array of property values
+     * @param mixed[]|null $data Associated array of property values
      *                      initializing the model
      */
-    public function __construct(array $data = null)
+    public function __construct(?array $data = null)
     {
         $this->container['to'] = $data['to'] ?? null;
         $this->container['from'] = $data['from'] ?? null;
diff --git a/lib/Model/Thumbnail.php b/lib/Model/Thumbnail.php
index 2f4691f..8c348cd 100755
--- a/lib/Model/Thumbnail.php
+++ b/lib/Model/Thumbnail.php
@@ -184,10 +184,10 @@ public function getModelName()
     /**
      * Constructor
      *
-     * @param mixed[] $data Associated array of property values
+     * @param mixed[]|null $data Associated array of property values
      *                      initializing the model
      */
-    public function __construct(array $data = null)
+    public function __construct(?array $data = null)
     {
         $this->container['small'] = $data['small'] ?? null;
         $this->container['medium'] = $data['medium'] ?? null;
diff --git a/lib/Model/UsVerification.php b/lib/Model/UsVerification.php
index b4bf287..3bc13bc 100755
--- a/lib/Model/UsVerification.php
+++ b/lib/Model/UsVerification.php
@@ -268,10 +268,10 @@ public function getObjectAllowableValues()
     /**
      * Constructor
      *
-     * @param mixed[] $data Associated array of property values
+     * @param mixed[]|null $data Associated array of property values
      *                      initializing the model
      */
-    public function __construct(array $data = null)
+    public function __construct(?array $data = null)
     {
         $this->container['id'] = $data['id'] ?? null;
         $this->container['recipient'] = $data['recipient'] ?? null;