diff --git a/Models/Supplier.php b/Models/Supplier.php
index a913a5d..7bf8a99 100755
--- a/Models/Supplier.php
+++ b/Models/Supplier.php
@@ -343,7 +343,7 @@ class Supplier
     /**
      * {@inheritdoc}
      */
-    public function jsonSerialize()
+    public function jsonSerialize() : mixed
     {
         return $this->toArray();
     }
diff --git a/Models/SupplierAttribute.php b/Models/SupplierAttribute.php
index 1bdce5e..4fd573b 100755
--- a/Models/SupplierAttribute.php
+++ b/Models/SupplierAttribute.php
@@ -97,7 +97,7 @@ class SupplierAttribute implements \JsonSerializable, ArrayableInterface
     /**
      * {@inheritdoc}
      */
-    public function jsonSerialize()
+    public function jsonSerialize() : mixed
     {
         return $this->toArray();
     }
diff --git a/Models/SupplierAttributeType.php b/Models/SupplierAttributeType.php
index 3bb1ee3..e943d60 100755
--- a/Models/SupplierAttributeType.php
+++ b/Models/SupplierAttributeType.php
@@ -152,7 +152,7 @@ class SupplierAttributeType implements \JsonSerializable, ArrayableInterface
     /**
      * {@inheritdoc}
      */
-    public function jsonSerialize()
+    public function jsonSerialize() : mixed
     {
         return $this->toArray();
     }
diff --git a/Models/SupplierAttributeTypeL11n.php b/Models/SupplierAttributeTypeL11n.php
index 058587a..0859e05 100755
--- a/Models/SupplierAttributeTypeL11n.php
+++ b/Models/SupplierAttributeTypeL11n.php
@@ -129,7 +129,7 @@ class SupplierAttributeTypeL11n implements \JsonSerializable, ArrayableInterface
     /**
      * {@inheritdoc}
      */
-    public function jsonSerialize()
+    public function jsonSerialize() : mixed
     {
         return $this->toArray();
     }
diff --git a/Models/SupplierAttributeValue.php b/Models/SupplierAttributeValue.php
index f25c1e2..5259532 100755
--- a/Models/SupplierAttributeValue.php
+++ b/Models/SupplierAttributeValue.php
@@ -248,7 +248,7 @@ class SupplierAttributeValue implements \JsonSerializable, ArrayableInterface
     /**
      * {@inheritdoc}
      */
-    public function jsonSerialize()
+    public function jsonSerialize() : mixed
     {
         return $this->toArray();
     }