diff --git a/README.md b/README.md
index d2952da..1548214 100644
--- a/README.md
+++ b/README.md
@@ -20,17 +20,17 @@ Run each command in the project root directory.
 
 ### Execute PHPUnit tests
 ```
-./vendor/bin/phpunit.phar -c ./phpunit.xml --testdox
+./vendor/bin/phpunit.phar --testdox
 ```
 
-### Execute PHPCS-Fixer checks
+### Execute fix PHPCS problems
 ```
-./vendor/bin/phpcs-fixer.phar fix ./src -v --diff
+./vendor/bin/phpcbf.phar
 ```
 
 ### Execute PHPCS checks
 ```
-./vendor/bin/phpcs.phar ./src --standard=PSR2
+./vendor/bin/phpcs.phar
 ```
 
 ### Execute PHPSTAN checks
diff --git a/composer.json b/composer.json
index 63617a2..bf26007 100644
--- a/composer.json
+++ b/composer.json
@@ -24,31 +24,31 @@
         "post-install-cmd": "Tooly\\ScriptHandler::installPharTools",
         "post-update-cmd": "Tooly\\ScriptHandler::installPharTools",
         "quickcheck": [
-            "./vendor/bin/phpunit.phar -c ./phpunit.xml --testdox",
-            "./vendor/bin/phpstan.phar analyse -l max ./src",
-            "./vendor/bin/phpcs.phar ./src --standard=PSR2"
+            "./vendor/bin/phpunit.phar --testdox",
+            "./vendor/bin/phpstan.phar analyse",
+            "./vendor/bin/phpcs.phar"
         ]
     },
     "extra": {
         "tools": {
             "phpunit": {
-                "url": "https://phar.phpunit.de/phpunit-8.5.1.phar",
-                "sign-url": "https://phar.phpunit.de/phpunit-8.5.1.phar.asc",
+                "url": "https://phar.phpunit.de/phpunit-9.2.3.phar",
+                "sign-url": "https://phar.phpunit.de/phpunit-9.2.3.phar.asc",
                 "force-replace": true
             },
             "phpcs": {
-                "url": "https://github.com/squizlabs/PHP_CodeSniffer/releases/download/3.5.3/phpcs.phar",
-                "sign-url": "https://github.com/squizlabs/PHP_CodeSniffer/releases/download/3.5.3/phpcs.phar.asc",
+                "url": "https://github.com/squizlabs/PHP_CodeSniffer/releases/download/3.5.5/phpcs.phar",
+                "sign-url": "https://github.com/squizlabs/PHP_CodeSniffer/releases/download/3.5.5/phpcs.phar.asc",
                 "force-replace": true
             },
-            "phpcs-fixer": {
-                "url": "https://github.com/FriendsOfPHP/PHP-CS-Fixer/releases/download/v2.16.1/php-cs-fixer.phar",
-                "sign-url": "https://github.com/FriendsOfPHP/PHP-CS-Fixer/releases/download/v2.16.1/php-cs-fixer.phar.asc",
+            "phpcbf": {
+                "url": "https://github.com/squizlabs/PHP_CodeSniffer/releases/download/3.5.5/phpcbf.phar",
+                "sign-url": "https://github.com/squizlabs/PHP_CodeSniffer/releases/download/3.5.5/phpcbf.phar.asc",
                 "force-replace": true
             },
             "phpstan": {
-                "url": "https://github.com/phpstan/phpstan/releases/download/0.11.19/phpstan.phar",
-                "sign-url": "https://github.com/phpstan/phpstan/releases/download/0.11.19/phpstan.phar.asc",
+                "url": "https://github.com/phpstan/phpstan/releases/download/0.12.29/phpstan.phar",
+                "sign-url": "https://github.com/phpstan/phpstan/releases/download/0.12.29/phpstan.phar.asc",
                 "force-replace": true
             }
         }
diff --git a/phpcs.xml b/phpcs.xml
new file mode 100644
index 0000000..fcfbddd
--- /dev/null
+++ b/phpcs.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0"?>
+<ruleset
+        name="PHP Coding Standards"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:noNamespaceSchemaLocation="vendor/squizlabs/php_codesniffer/phpcs.xsd">
+
+    <!-- set config paths to check-packages -->
+    <config name="ignore_warnings_on_exit" value="true"/>
+    <config name="ignore_errors_on_exit" value="true"/>
+
+    <!-- set basic phpcs config -->
+    <arg name="extensions" value="php"/>
+    <arg name="colors"/>
+
+    <!-- Show progress of the run -->
+    <arg value="p"/>
+
+    <!-- set ruleset to use -->
+    <rule ref="PSR12"/>
+
+    <!-- set paths to check -->
+    <file>src</file>
+    <file>tests</file>
+</ruleset>
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..6b7a364
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,11 @@
+parameters:
+    level: max
+
+    inferPrivatePropertyTypeFromConstructor: true
+    checkMissingIterableValueType: false
+
+    fileExtensions:
+        - php
+
+    paths:
+        - %currentWorkingDirectory%/src
diff --git a/src/Enum.php b/src/Enum.php
index 6c94f48..430f503 100644
--- a/src/Enum.php
+++ b/src/Enum.php
@@ -10,7 +10,7 @@ abstract class Enum
 {
     protected string $value;
 
-    public function __construct(string $value = '')
+    final public function __construct(string $value = '')
     {
         $this->setValue($value);
     }