diff --git a/Plugin/Quote/Address/Total/ShippingPlugin.php b/Plugin/Quote/Address/Total/ShippingPlugin.php
index 8b80d35..b22d676 100644
--- a/Plugin/Quote/Address/Total/ShippingPlugin.php
+++ b/Plugin/Quote/Address/Total/ShippingPlugin.php
@@ -54,14 +54,14 @@ public function aroundCollect(
 
         if (!$this->customShippingRateHelper->isEnabled($storeId)
             || $address->getAddressType() != Address::ADDRESS_TYPE_SHIPPING
-            || strpos((string) $method, Carrier::CODE) === false
+            || !str_contains((string) $method, Carrier::CODE)
         ) {
             return $proceed($quote, $shippingAssignment, $total);
         }
 
         $customShippingOption = $this->getCustomShippingJsonToArray($method, $address, $storeId);
 
-        if ($customShippingOption && strpos((string) $method, $customShippingOption['code']) !== false) {
+        if ($customShippingOption && str_contains((string) $method, (string) $customShippingOption['code'])) {
             //update shipping code
             $shipping->setMethod($customShippingOption['code']);
             $address->setShippingMethod($customShippingOption['code']);
@@ -79,7 +79,7 @@ protected function updateCustomRate($address, $customShippingOption)
     {
         if ($selectedRate = $this->getSelectedShippingRate($address, $customShippingOption['code'])) {
             $cost = (float) $customShippingOption['rate'];
-            $description = trim($customShippingOption['description']);
+            $description = trim((string) $customShippingOption['description']);
 
             $selectedRate->setPrice($cost);
             $selectedRate->setCost($cost);
@@ -116,7 +116,7 @@ private function getCustomShippingJsonToArray($json, $address, $storeId = null)
             return $this->formatShippingArray($jsonToArray);
         }
 
-        $jsonToArray = (array)json_decode($json, true);
+        $jsonToArray = (array)json_decode((string) $json, true);
 
         if (is_array($jsonToArray) && count($jsonToArray) == 4) {
             return $this->formatShippingArray($jsonToArray);
diff --git a/composer.json b/composer.json
index ebd5a25..62c5d3e 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
         "free shipping"
     ],
     "type": "magento2-module",
-    "version": "1.8.2",
+    "version": "1.8.3",
     "license": [
         "proprietary"
     ],
@@ -36,10 +36,7 @@
         }
     ],
     "require": {
-        "php": "~8.1.0|~8.2.0|~8.3.0",
-        "magento/module-backend": "102.0.*",
-        "magento/framework": "103.0.*",
-        "magepal/magento2-core": ">=1.1.10"
+        "php": "~8.3.0|~8.4.0"
     },
     "autoload": {
         "files": [
diff --git a/rector.php b/rector.php
new file mode 100644
index 0000000..bbeb318
--- /dev/null
+++ b/rector.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\Class_\InlineConstructorDefaultToPropertyRector;
+use Rector\Config\RectorConfig;
+use Rector\Set\ValueObject\LevelSetList;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->paths([
+        __DIR__ . '/',
+    ]);
+
+    $rectorConfig->sets([
+        LevelSetList::UP_TO_PHP_84
+    ]);
+};