diff --git a/Controller/ApiController.php b/Controller/ApiController.php
index af39d86..8eeef64 100755
--- a/Controller/ApiController.php
+++ b/Controller/ApiController.php
@@ -279,7 +279,7 @@ final class ApiController extends Controller
 
         $status = !\is_dir($pdfDir) ? \mkdir($pdfDir, 0755, true) : true;
         if ($status === false) {
-            $response->set($request->uri->__toString(), new FormValidation($status));
+            $response->set($request->uri->__toString(), new FormValidation(['status' => $status]));
             $response->header->status = RequestStatusCode::R_400;
 
             return;
diff --git a/Controller/BackendController.php b/Controller/BackendController.php
index abc313c..2a9286f 100755
--- a/Controller/BackendController.php
+++ b/Controller/BackendController.php
@@ -293,6 +293,7 @@ final class BackendController extends Controller
 
         $view->addData('currentCustomerRegion', $currentCustomerRegion);
 
+        $annualCustomerRegion = [];
         for ($i = 1; $i < 11; ++$i) {
             $annualCustomerRegion[] = [
                 'year'    => 2020 - 10 + $i,
@@ -355,6 +356,7 @@ final class BackendController extends Controller
 
         $view->addData('currentCustomerRegion', $currentCustomerRegion);
 
+        $annualCustomerRegion = [];
         for ($i = 1; $i < 11; ++$i) {
             $annualCustomerRegion[] = [
                 'year'    => 2020 - 10 + $i,
@@ -378,7 +380,9 @@ final class BackendController extends Controller
             ];
         }
 
-        \uasort($currentCustomersRep, function($a, $b) { return $b['customers'] <=> $a['customers']; });
+        \uasort($currentCustomersRep, function($a, $b) {
+            return $b['customers'] <=> $a['customers'];
+        });
 
         $view->addData('currentCustomersRep', $currentCustomersRep);
 
@@ -405,7 +409,9 @@ final class BackendController extends Controller
             ];
         }
 
-        \uasort($currentCustomersCountry, function($a, $b) { return $b['customers'] <=> $a['customers']; });
+        \uasort($currentCustomersCountry, function($a, $b) {
+            return $b['customers'] <=> $a['customers'];
+        });
 
         $view->addData('currentCustomersCountry', $currentCustomersCountry);
 
@@ -501,6 +507,7 @@ final class BackendController extends Controller
 
         $view->addData('currentCustomerRegion', $currentCustomerRegion);
 
+        $annualCustomerRegion = [];
         for ($i = 1; $i < 11; ++$i) {
             $annualCustomerRegion[] = [
                 'year'    => 2020 - 10 + $i,
@@ -524,7 +531,9 @@ final class BackendController extends Controller
             ];
         }
 
-        \uasort($currentCustomersRep, function($a, $b) { return $b['customers'] <=> $a['customers']; });
+        \uasort($currentCustomersRep, function($a, $b) {
+            return $b['customers'] <=> $a['customers'];
+        });
 
         $view->addData('currentCustomersRep', $currentCustomersRep);
 
diff --git a/Models/Bill.php b/Models/Bill.php
index 4529760..a2c3b1d 100755
--- a/Models/Bill.php
+++ b/Models/Bill.php
@@ -55,9 +55,7 @@ class Bill implements \JsonSerializable
      * @var int|BillType
      * @since 1.0.0
      */
-    public int |
-
-BillType $type = 0;
+    public int|BillType $type = 0;
 
     /**
      * Bill status.
diff --git a/Models/BillElement.php b/Models/BillElement.php
index 9a8d03b..64314e5 100755
--- a/Models/BillElement.php
+++ b/Models/BillElement.php
@@ -91,9 +91,7 @@ class BillElement implements \JsonSerializable
      */
     public int $promotion = 0;
 
-    public int |
-
-Bill $bill = 0;
+    public int|Bill $bill = 0;
 
     /**
      * Constructor.
diff --git a/Models/BillType.php b/Models/BillType.php
index af50dfc..8f14cee 100755
--- a/Models/BillType.php
+++ b/Models/BillType.php
@@ -43,9 +43,7 @@ class BillType
      *
      * @var string|BillTypeL11n
      */
-    protected string |
-
-BillTypeL11n $l11n;
+    protected string|BillTypeL11n $l11n;
 
     /**
      * Constructor.
diff --git a/Models/BillTypeL11n.php b/Models/BillTypeL11n.php
index df51dfd..6d1f6cf 100755
--- a/Models/BillTypeL11n.php
+++ b/Models/BillTypeL11n.php
@@ -41,9 +41,7 @@ class BillTypeL11n implements \JsonSerializable, ArrayableInterface
      * @var int
      * @since 1.0.0
      */
-    protected int |
-
-BillType $type = 0;
+    protected int|BillType $type = 0;
 
     /**
      * Language.
diff --git a/composer.json b/composer.json
index 7ad134b..7cf5769 100755
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,7 @@
     "require-dev": {
         "phpunit/phpunit": ">=9.4",
         "friendsofphp/php-cs-fixer": ">=3.0",
-        "squizlabs/php_codesniffer": ">=3.5",
+        "squizlabs/php_codesniffer": ">=3.6",
         "phpmd/phpmd": ">=2.9",
         "phpstan/phpstan": ">=0.12.58",
         "phan/phan": ">=3.2.6"