diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 690ec0e..08fbbd5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,10 +14,16 @@ jobs:
       matrix:
         php-versions: ['8.0', '8.1', '8.2', '8.3']
         coverage: ['pcov']
+        code-style: ['no']
         code-analysis: ['no']
         include:
           - php-versions: '7.4'
             coverage: 'none'
+            code-style: 'yes'
+            code-analysis: 'yes'
+          - php-versions: '8.4'
+            coverage: 'none'
+            code-style: 'no'
             code-analysis: 'yes'
     steps:
       - name: Checkout
@@ -48,8 +54,8 @@ jobs:
         run: composer install --no-progress --prefer-dist --optimize-autoloader
 
       - name: Code Analysis (PHP CS-Fixer)
-        if: matrix.code-analysis == 'yes'
-        run: php vendor/bin/php-cs-fixer fix --dry-run --diff
+        if: matrix.code-style == 'yes'
+        run: PHP_CS_FIXER_IGNORE_ENV=true php vendor/bin/php-cs-fixer fix --dry-run --diff
 
       - name: Code Analysis (PHPStan)
         if: matrix.code-analysis == 'yes'
diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 8733752..f9d4b7a 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -7,7 +7,11 @@
 $config = new PhpCsFixer\Config();
 $config->setRules([
     '@PSR1' => true,
-    '@Symfony' => true
+    '@Symfony' => true,
+    'nullable_type_declaration' => [
+        'syntax' => 'question_mark',
+    ],
+    'nullable_type_declaration_for_default_null_value' => true,
 ]);
 $config->setFinder($finder);
 return $config;
\ No newline at end of file
diff --git a/composer.json b/composer.json
index ccab9bf..2d26c23 100644
--- a/composer.json
+++ b/composer.json
@@ -37,11 +37,11 @@
         }
     },
     "require-dev": {
-        "friendsofphp/php-cs-fixer": "^3.56",
-        "phpstan/phpstan": "^1.11",
+        "friendsofphp/php-cs-fixer": "^3.64",
+        "phpstan/phpstan": "^1.12",
         "phpstan/phpstan-phpunit": "^1.4",
         "phpstan/phpstan-strict-rules": "^1.6",
-        "phpstan/extension-installer": "^1.3",
+        "phpstan/extension-installer": "^1.4",
         "phpunit/phpunit" : "^9.6"
     },
     "scripts": {
diff --git a/phpstan.neon b/phpstan.neon
index 0f7b90a..903f25e 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -1,7 +1,24 @@
 parameters:
   level: 9
+  reportUnmatchedIgnoredErrors: false
   ignoreErrors:
   -
     message: "#^.* will always evaluate to true\\.$#"
     path: tests/*
     count: 1
+  -
+    message: "#^Offset .* in isset\\(\\) always exists and is not nullable\\.$#"
+    path: lib/functions.php
+    count: 3
+  -
+    message: "#^Result of && is always true\\.$#"
+    path: lib/functions.php
+    count: 1
+  -
+    message: "#^Strict comparison using !== between '' and non-falsy-string will always evaluate to true\\.$#"
+    path: lib/functions.php
+    count: 1
+  -
+    message: "#^Strict comparison using === between false and string will always evaluate to false\\.$#"
+    path: lib/functions.php
+    count: 2