diff --git a/src/Definition/Type.php b/src/Definition/Type.php
index f68c6a61..6cb15b30 100644
--- a/src/Definition/Type.php
+++ b/src/Definition/Type.php
@@ -726,7 +726,7 @@ public function getDirectlyImplementedInterfaces(): array
             }
             if ($this->isContainedType()) {
                 $interfaces[] = PHPFHIR_INTERFACE_CONTAINED_TYPE;
-            } else if ($this->getKind() !== TypeKind::PRIMITIVE) {
+            } else {
                 $interfaces[] = PHPFHIR_INTERFACE_TYPE;
             }
         } elseif ($this->isContainedType() && !$parentType->isContainedType()) {
@@ -749,10 +749,7 @@ public function getDirectlyUsedTraits(): array
             }
             $traits[] = PHPFHIR_TRAIT_VALIDATION_ASSERTIONS;
             $traits[] = PHPFHIR_TRAIT_CHANGE_TRACKING;
-
-            if ($this->getKind() !== TypeKind::PRIMITIVE) {
-                $traits[] = PHPFHIR_TRAIT_XMLNS;
-            }
+            $traits[] = PHPFHIR_TRAIT_XMLNS;
         }
 
         return $traits;
diff --git a/template/interfaces/phpfhir_type.php b/template/interfaces/phpfhir_type.php
index cdecf952..359dde4f 100644
--- a/template/interfaces/phpfhir_type.php
+++ b/template/interfaces/phpfhir_type.php
@@ -42,11 +42,6 @@
 
  */
 interface <?php echo PHPFHIR_INTERFACE_TYPE; ?> extends \JsonSerializable {
-    /**
-     * @param array|null $data
-     */
-    public function __construct(?array $data = null);
-
     /**
      * Returns the FHIR name represented by this Type
      * @return string
diff --git a/template/types/serialization/json/default.php b/template/types/serialization/json/default.php
index 9b23cfd8..2d42095e 100644
--- a/template/types/serialization/json/default.php
+++ b/template/types/serialization/json/default.php
@@ -26,7 +26,7 @@
     /**
      * @return \stdClass
      */
-    public function jsonSerialize()
+    public function jsonSerialize(): \stdClass
     {
 <?php if (null !== $type->getParentType()) : ?>
         $out = parent::jsonSerialize();
diff --git a/template/types/serialization/json/list.php b/template/types/serialization/json/list.php
deleted file mode 100644
index 18ad5585..00000000
--- a/template/types/serialization/json/list.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php declare(strict_types=1);
-
-/*
- * Copyright 2018-2024 Daniel Carbone (daniel.p.carbone@gmail.com)
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-ob_start(); ?>
-    /**
-     * @return null|string
-     */
-    public function jsonSerialize()
-    {
-        return $this->getValue();
-    }
-<?php return ob_get_clean();
diff --git a/template/types/serialization/json/primitive.php b/template/types/serialization/json/primitive.php
index ad0ceb34..6b1e0089 100644
--- a/template/types/serialization/json/primitive.php
+++ b/template/types/serialization/json/primitive.php
@@ -28,7 +28,7 @@
      * @return <?php echo TypeHintUtils::primitivePHPValueTypeDoc($config, $type->getPrimitiveType(), true, false); ?>
 
      */
-    public function jsonSerialize()
+    public function jsonSerialize(): <?php echo TypeHintUtils::primitivePHPValueTypeDoc($config, $type->getPrimitiveType(), true, false); ?>
     {
 <?php if ($typeKind === TypeKind::PRIMITIVE && str_contains($type->getFHIRName(), 'unsigned')) : ?>
         return intval($this->getValue(), 10);
diff --git a/template/types/serialization/json/resource_container.php b/template/types/serialization/json/resource_container.php
index a963dd87..e8f9a000 100644
--- a/template/types/serialization/json/resource_container.php
+++ b/template/types/serialization/json/resource_container.php
@@ -20,9 +20,9 @@
 
 ob_start(); ?>
     /**
-     * @return object|null
+     * @return null|object
      */
-    public function jsonSerialize()
+    public function jsonSerialize(): null|object
     {<?php foreach($properties as $property) : ?>
 
         if (null !== ($v = $this->get<?php echo ucfirst($property->getName()); ?>())) {