diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
index a5b5f227269d..177f8600e55d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
@@ -483,7 +483,7 @@ public String prependSlashToDataTypeOnlyIfNecessary(String dataType) {
             return dataType;
         }
 
-        return  "\\" + dataType;
+        return "\\" + dataType;
     }
 
     /**
diff --git a/modules/openapi-generator/src/main/resources/php-symfony/model_generic.mustache b/modules/openapi-generator/src/main/resources/php-symfony/model_generic.mustache
index 5b093b479d46..2c3636040279 100644
--- a/modules/openapi-generator/src/main/resources/php-symfony/model_generic.mustache
+++ b/modules/openapi-generator/src/main/resources/php-symfony/model_generic.mustache
@@ -12,9 +12,11 @@ class {{classname}} {{#parentSchema}}extends {{{parent}}} {{/parentSchema}}
         parent::__construct($data);
 
         {{/parentSchema}}
-        {{#vars}}
-        $this->{{name}} = $data['{{name}}'] ?? null;
-        {{/vars}}
+        if (is_array($data)) {
+            {{#vars}}
+            $this->{{name}} = array_key_exists('{{name}}', $data) ? $data['{{name}}'] : $this->{{name}};
+            {{/vars}}
+        }
     }
     {{#vars}}
 
diff --git a/modules/openapi-generator/src/main/resources/php-symfony/model_variables.mustache b/modules/openapi-generator/src/main/resources/php-symfony/model_variables.mustache
index 4a77c9a46385..7855e1e1c457 100644
--- a/modules/openapi-generator/src/main/resources/php-symfony/model_variables.mustache
+++ b/modules/openapi-generator/src/main/resources/php-symfony/model_variables.mustache
@@ -98,4 +98,4 @@
     {{/minItems}}
 {{/hasValidation}}
      */
-    protected {{{vendorExtensions.x-parameter-type}}} ${{name}} = null;
+    protected {{{vendorExtensions.x-parameter-type}}} ${{name}} = {{#defaultValue}}{{{defaultValue}}}{{/defaultValue}}{{^defaultValue}}null{{/defaultValue}};
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/ApiResponse.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/ApiResponse.php
index 21b86eeae337..218d4f85afb4 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/ApiResponse.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/ApiResponse.php
@@ -74,9 +74,11 @@ class ApiResponse
      */
     public function __construct(array $data = null)
     {
-        $this->code = $data['code'] ?? null;
-        $this->type = $data['type'] ?? null;
-        $this->message = $data['message'] ?? null;
+        if (is_array($data)) {
+            $this->code = array_key_exists('code', $data) ? $data['code'] : $this->code;
+            $this->type = array_key_exists('type', $data) ? $data['type'] : $this->type;
+            $this->message = array_key_exists('message', $data) ? $data['message'] : $this->message;
+        }
     }
 
     /**
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Category.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Category.php
index fac8878d4644..2ea80a897b63 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Category.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Category.php
@@ -67,8 +67,10 @@ class Category
      */
     public function __construct(array $data = null)
     {
-        $this->id = $data['id'] ?? null;
-        $this->name = $data['name'] ?? null;
+        if (is_array($data)) {
+            $this->id = array_key_exists('id', $data) ? $data['id'] : $this->id;
+            $this->name = array_key_exists('name', $data) ? $data['name'] : $this->name;
+        }
     }
 
     /**
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Order.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Order.php
index 72c6a15db0dc..d902d49a2ab3 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Order.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Order.php
@@ -93,7 +93,7 @@ class Order
      * @Assert\Type("bool")
      * @Type("bool")
      */
-    protected ?bool $complete = null;
+    protected ?bool $complete = false;
 
     /**
      * Constructor
@@ -101,12 +101,14 @@ class Order
      */
     public function __construct(array $data = null)
     {
-        $this->id = $data['id'] ?? null;
-        $this->petId = $data['petId'] ?? null;
-        $this->quantity = $data['quantity'] ?? null;
-        $this->shipDate = $data['shipDate'] ?? null;
-        $this->status = $data['status'] ?? null;
-        $this->complete = $data['complete'] ?? null;
+        if (is_array($data)) {
+            $this->id = array_key_exists('id', $data) ? $data['id'] : $this->id;
+            $this->petId = array_key_exists('petId', $data) ? $data['petId'] : $this->petId;
+            $this->quantity = array_key_exists('quantity', $data) ? $data['quantity'] : $this->quantity;
+            $this->shipDate = array_key_exists('shipDate', $data) ? $data['shipDate'] : $this->shipDate;
+            $this->status = array_key_exists('status', $data) ? $data['status'] : $this->status;
+            $this->complete = array_key_exists('complete', $data) ? $data['complete'] : $this->complete;
+        }
     }
 
     /**
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Pet.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Pet.php
index 6a400e7c2486..0ba0114642f6 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Pet.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Pet.php
@@ -107,12 +107,14 @@ class Pet
      */
     public function __construct(array $data = null)
     {
-        $this->id = $data['id'] ?? null;
-        $this->category = $data['category'] ?? null;
-        $this->name = $data['name'] ?? null;
-        $this->photoUrls = $data['photoUrls'] ?? null;
-        $this->tags = $data['tags'] ?? null;
-        $this->status = $data['status'] ?? null;
+        if (is_array($data)) {
+            $this->id = array_key_exists('id', $data) ? $data['id'] : $this->id;
+            $this->category = array_key_exists('category', $data) ? $data['category'] : $this->category;
+            $this->name = array_key_exists('name', $data) ? $data['name'] : $this->name;
+            $this->photoUrls = array_key_exists('photoUrls', $data) ? $data['photoUrls'] : $this->photoUrls;
+            $this->tags = array_key_exists('tags', $data) ? $data['tags'] : $this->tags;
+            $this->status = array_key_exists('status', $data) ? $data['status'] : $this->status;
+        }
     }
 
     /**
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Tag.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Tag.php
index 3ee1398a4840..08f6550d182a 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Tag.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/Tag.php
@@ -66,8 +66,10 @@ class Tag
      */
     public function __construct(array $data = null)
     {
-        $this->id = $data['id'] ?? null;
-        $this->name = $data['name'] ?? null;
+        if (is_array($data)) {
+            $this->id = array_key_exists('id', $data) ? $data['id'] : $this->id;
+            $this->name = array_key_exists('name', $data) ? $data['name'] : $this->name;
+        }
     }
 
     /**
diff --git a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/User.php b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/User.php
index 179ec3f173b6..129657df957c 100644
--- a/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/User.php
+++ b/samples/server/petstore/php-symfony/SymfonyBundle-php/Model/User.php
@@ -116,14 +116,16 @@ class User
      */
     public function __construct(array $data = null)
     {
-        $this->id = $data['id'] ?? null;
-        $this->username = $data['username'] ?? null;
-        $this->firstName = $data['firstName'] ?? null;
-        $this->lastName = $data['lastName'] ?? null;
-        $this->email = $data['email'] ?? null;
-        $this->password = $data['password'] ?? null;
-        $this->phone = $data['phone'] ?? null;
-        $this->userStatus = $data['userStatus'] ?? null;
+        if (is_array($data)) {
+            $this->id = array_key_exists('id', $data) ? $data['id'] : $this->id;
+            $this->username = array_key_exists('username', $data) ? $data['username'] : $this->username;
+            $this->firstName = array_key_exists('firstName', $data) ? $data['firstName'] : $this->firstName;
+            $this->lastName = array_key_exists('lastName', $data) ? $data['lastName'] : $this->lastName;
+            $this->email = array_key_exists('email', $data) ? $data['email'] : $this->email;
+            $this->password = array_key_exists('password', $data) ? $data['password'] : $this->password;
+            $this->phone = array_key_exists('phone', $data) ? $data['phone'] : $this->phone;
+            $this->userStatus = array_key_exists('userStatus', $data) ? $data['userStatus'] : $this->userStatus;
+        }
     }
 
     /**