diff --git a/.gitattributes b/.gitattributes
index 509ef43..c605075 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -7,4 +7,4 @@ tools/*         binary
 /phpunit.xml    export-ignore
 /.phive/phars.xml      export-ignore
 /.phive/phars.xml      export-ignore
-/.php_cs.dist    export-ignore
+/.php-cs-fixer.cache    export-ignore
diff --git a/.github/workflows/analyzers.yaml b/.github/workflows/analyzers.yaml
index 5043a51..e74b031 100644
--- a/.github/workflows/analyzers.yaml
+++ b/.github/workflows/analyzers.yaml
@@ -7,7 +7,7 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.0']
+                php-versions: ['8.0', '8.1']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.github/workflows/code-style.yaml b/.github/workflows/code-style.yaml
index c8a982f..c6c3e1d 100644
--- a/.github/workflows/code-style.yaml
+++ b/.github/workflows/code-style.yaml
@@ -7,7 +7,7 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.0']
+                php-versions: ['8.0', '8.1']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
@@ -22,4 +22,4 @@ jobs:
             - name: Install dependencies
               run: composer update --prefer-dist --no-progress --no-suggest ${{ matrix.composer-options }}
             - name: Run the tests
-              run: ./tools/php-cs-fixer.phar fix --dry-run
+              run: PHP_CS_FIXER_IGNORE_ENV=1 ./tools/php-cs-fixer.phar fix --dry-run
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 4c130dd..87c98bf 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -7,7 +7,7 @@ jobs:
         strategy:
             matrix:
                 operating-system: [ubuntu-latest]
-                php-versions: ['8.0']
+                php-versions: ['8.0', '8.1']
             fail-fast: false
         name: PHP ${{ matrix.php-versions }} @ ${{ matrix.operating-system }}
         steps:
diff --git a/.gitignore b/.gitignore
index ff2edfc..b85ce0f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,5 @@
 /vendor/
 composer.lock
 .phpunit.result.cache
-.php_cs.cache
+.php-cs-fixer.cache
 
diff --git a/.phive/phars.xml b/.phive/phars.xml
index 4e3aab8..980defa 100644
--- a/.phive/phars.xml
+++ b/.phive/phars.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phive xmlns="https://phar.io/phive">
-  <phar name="psalm" version="^4.3.1" installed="4.12.0" location="./tools/psalm.phar" copy="true"/>
-  <phar name="php-cs-fixer" version="^2.18.2" installed="2.19.0" location="./tools/php-cs-fixer.phar" copy="true"/>
+  <phar name="psalm" version="^4.13.1" installed="4.13.1" location="./tools/psalm.phar" copy="true"/>
+  <phar name="php-cs-fixer" version="^3.3.2" installed="3.3.2" location="./tools/php-cs-fixer.phar" copy="true"/>
 </phive>
diff --git a/.php_cs.dist b/.php-cs-fixer.dist.php
similarity index 93%
rename from .php_cs.dist
rename to .php-cs-fixer.dist.php
index 31d786a..b2fc9eb 100644
--- a/.php_cs.dist
+++ b/.php-cs-fixer.dist.php
@@ -1,6 +1,6 @@
 <?php
 
-return PhpCsFixer\Config::create()
+return (new PhpCsFixer\Config())
     ->setFinder(
         \Symfony\Component\Finder\Finder::create()
             ->in([
@@ -24,7 +24,9 @@
         'list_syntax' => [
             'syntax' => 'short',
         ],
-        'lowercase_constants' => true,
+        'constant_case' => [
+            'case' => 'lower',
+        ],
         'multiline_comment_opening_closing' => true,
         'native_function_casing' => true,
         'no_empty_phpdoc' => true,
diff --git a/composer.json b/composer.json
index d890b85..5109da1 100644
--- a/composer.json
+++ b/composer.json
@@ -23,10 +23,10 @@
         "php": "^8.0",
         "ext-soap": "*",
         "ext-dom": "*",
-        "azjezz/psl": "^1.7",
+        "azjezz/psl": "^1.9",
         "php-soap/engine": "^1.1",
         "php-soap/wsdl": "^1.0",
-        "symfony/options-resolver": "^5.3"
+        "symfony/options-resolver": "^5.3 || ^6.0"
     },
     "require-dev": {
         "php-soap/engine-integration-tests": "^1.1",
diff --git a/tools/php-cs-fixer.phar b/tools/php-cs-fixer.phar
index 6905c34..55d1ba0 100755
Binary files a/tools/php-cs-fixer.phar and b/tools/php-cs-fixer.phar differ
diff --git a/tools/psalm.phar b/tools/psalm.phar
index f9ccfd5..0452e69 100755
Binary files a/tools/psalm.phar and b/tools/psalm.phar differ