diff --git a/src/MoneySerializer.php b/src/MoneySerializer.php
index 4b4f7a8..6d0cec1 100644
--- a/src/MoneySerializer.php
+++ b/src/MoneySerializer.php
@@ -7,5 +7,5 @@
  */
 interface MoneySerializer
 {
-    public function serialize(Money $money): mixed;
+    public function serialize(Money $money);
 }
diff --git a/src/MoneySerializerTrait.php b/src/MoneySerializerTrait.php
index 813bae0..ced876f 100644
--- a/src/MoneySerializerTrait.php
+++ b/src/MoneySerializerTrait.php
@@ -58,7 +58,7 @@ public function serializeByArray()
      * Serialize by serializer.
      *
      * @param  \Cknow\Money\MoneySerializer  $serializer
-     * @return string
+     * @return mixed
      */
     public function serializeBySerializer(MoneySerializer $serializer)
     {
diff --git a/src/Serializer/ArrayMoneySerializer.php b/src/Serializer/ArrayMoneySerializer.php
index 87f326e..1502264 100644
--- a/src/Serializer/ArrayMoneySerializer.php
+++ b/src/Serializer/ArrayMoneySerializer.php
@@ -10,15 +10,15 @@ class ArrayMoneySerializer implements MoneySerializer
     /**
      * Formats a Money object as string.
      *
-     * @param  \Money\Money  $money
-     * @return mixed
+     * @param  \Cknow\Money\Money  $money
+     * @return array
      */
-    public function serialize(Money $money): mixed
+    public function serialize(Money $money)
     {
         return array_merge(
             $money->getAttributes(),
             $money->getMoney()->jsonSerialize(),
-            ['formatted' => $money->render()]
+            ['formatted' => $money->format()]
         );
     }
 }
diff --git a/src/Serializer/DecimalMoneySerializer.php b/src/Serializer/DecimalMoneySerializer.php
index 09ed163..c76fb2a 100644
--- a/src/Serializer/DecimalMoneySerializer.php
+++ b/src/Serializer/DecimalMoneySerializer.php
@@ -10,10 +10,10 @@ class DecimalMoneySerializer implements MoneySerializer
     /**
      * Formats a Money object as string.
      *
-     * @param  \Money\Money  $money
-     * @return mixed
+     * @param  \Cknow\Money\Money  $money
+     * @return string
      */
-    public function serialize(Money $money): mixed
+    public function serialize(Money $money)
     {
         return $money->formatByDecimal();
     }
diff --git a/src/Serializer/IntegerMoneySerializer.php b/src/Serializer/IntegerMoneySerializer.php
index 61b98fd..0ef8300 100644
--- a/src/Serializer/IntegerMoneySerializer.php
+++ b/src/Serializer/IntegerMoneySerializer.php
@@ -10,10 +10,10 @@ class IntegerMoneySerializer implements MoneySerializer
     /**
      * Formats a Money object as string.
      *
-     * @param  \Money\Money  $money
-     * @return mixed
+     * @param  \Cknow\Money\Money  $money
+     * @return int
      */
-    public function serialize(Money $money): mixed
+    public function serialize(Money $money)
     {
         return (int) $money->getAmount();
     }
diff --git a/src/Serializer/StringMoneySerializer.php b/src/Serializer/StringMoneySerializer.php
index 16e6fb7..fb764d1 100644
--- a/src/Serializer/StringMoneySerializer.php
+++ b/src/Serializer/StringMoneySerializer.php
@@ -10,11 +10,11 @@ class StringMoneySerializer implements MoneySerializer
     /**
      * Formats a Money object as string.
      *
-     * @param  \Money\Money  $money
-     * @return mixed
+     * @param  \Cknow\Money\Money  $money
+     * @return string
      */
-    public function serialize(Money $money): mixed
+    public function serialize(Money $money)
     {
-        return (string) $money->formatByIntl();
+        return (string) $money->format();
     }
 }