diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index efdad92..23ada41 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of PHP CS Fixer / PHPUnit Constraint XmlMatchesXsd.
  *
@@ -14,14 +16,14 @@
 use PhpCsFixer\Finder;
 
 $header = <<<'EOF'
-This file is part of PHP CS Fixer / PHPUnit Constraint XmlMatchesXsd.
+    This file is part of PHP CS Fixer / PHPUnit Constraint XmlMatchesXsd.
 
-(c) SpacePossum
-    Dariusz Rumiński <dariusz.ruminski@gmail.com>
+    (c) SpacePossum
+        Dariusz Rumiński <dariusz.ruminski@gmail.com>
 
-This source file is subject to the MIT license that is bundled
-with this source code in the file LICENSE.
-EOF;
+    This source file is subject to the MIT license that is bundled
+    with this source code in the file LICENSE.
+    EOF;
 
 $finder = Finder::create()
     ->exclude('tests/Fixtures')
@@ -32,9 +34,10 @@
 return (new Config())
     ->setRiskyAllowed(true)
     ->setRules([
+        '@auto' => true,
+        '@auto:risky' => true,
         '@PhpCsFixer' => true,
         '@PhpCsFixer:risky' => true,
-        '@PHPUnit60Migration:risky' => true,
         'header_comment' => ['header' => $header],
     ])
     ->setFinder($finder)
diff --git a/dev-tools/composer.json b/dev-tools/composer.json
index ce71027..bb2c7a8 100644
--- a/dev-tools/composer.json
+++ b/dev-tools/composer.json
@@ -1,12 +1,12 @@
 {
     "require": {
-        "php": "^8.1"
+        "php": "^8.5"
     },
     "require-dev": {
-        "ergebnis/composer-normalize": "*",
-        "maglnet/composer-require-checker": "^3.8",
+        "ergebnis/composer-normalize": "^2.50",
+        "maglnet/composer-require-checker": "^4.21",
         "mi-schi/phpmd-extension": "^4.3",
-        "php-cs-fixer/shim": "^3.68.5",
+        "php-cs-fixer/shim": "^3.94.2",
         "phpmd/phpmd": "^2.15"
     },
     "config": {
diff --git a/src/Constraint/XmlMatchesXsd.php b/src/Constraint/XmlMatchesXsd.php
index ecb18f2..5cafd12 100644
--- a/src/Constraint/XmlMatchesXsd.php
+++ b/src/Constraint/XmlMatchesXsd.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of PHP CS Fixer / PHPUnit Constraint XmlMatchesXsd.
  *
@@ -12,6 +14,4 @@
 
 namespace PhpCsFixer\PhpunitConstraintXmlMatchesXsd\Constraint;
 
-use PHPUnit\Runner\Version;
-
 class_alias(XmlMatchesXsdForV9::class, XmlMatchesXsd::class);
diff --git a/src/Constraint/XmlMatchesXsdForV9.php b/src/Constraint/XmlMatchesXsdForV9.php
index 0d2eadf..d1c42ad 100644
--- a/src/Constraint/XmlMatchesXsdForV9.php
+++ b/src/Constraint/XmlMatchesXsdForV9.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of PHP CS Fixer / PHPUnit Constraint XmlMatchesXsd.
  *
@@ -110,7 +112,7 @@ private function stringMatches($other)
         return $result;
     }
 
-    private function setXMLConstraintErrors()
+    private function setXMLConstraintErrors(): void
     {
         foreach (libxml_get_errors() as $error) {
             if (LIBXML_ERR_WARNING === $error->level) {
diff --git a/tests/Constraint/XmlMatchesXsdTest.php b/tests/Constraint/XmlMatchesXsdTest.php
index 1128291..3935c39 100644
--- a/tests/Constraint/XmlMatchesXsdTest.php
+++ b/tests/Constraint/XmlMatchesXsdTest.php
@@ -1,5 +1,7 @@
 <?php
 
+declare(strict_types=1);
+
 /*
  * This file is part of PHP CS Fixer / PHPUnit Constraint XmlMatchesXsd.
  *
@@ -22,7 +24,7 @@
  */
 final class XmlMatchesXsdTest extends TestCase
 {
-    public function testAssertXMLMatchesXSD()
+    public function testAssertXMLMatchesXSD(): void
     {
         $constraint = new XmlMatchesXsd($this->getXSD());
         $sampleFile = $this->getAssetsDir().'xliff_sample.xml';
@@ -42,14 +44,14 @@ public function testAssertXMLMatchesXSD()
         self::assertTrue($constraint->evaluate($content, '', true));
     }
 
-    public function testXMLValidConstraintBasics()
+    public function testXMLValidConstraintBasics(): void
     {
         $constraint = new XmlMatchesXsd('');
         self::assertSame(1, $constraint->count());
         self::assertSame('matches XSD', $constraint->toString());
     }
 
-    public function testXMLValidConstraintFalse()
+    public function testXMLValidConstraintFalse(): void
     {
         $this->expectException(
             'PHPUnit\Framework\ExpectationFailedException'
@@ -62,7 +64,7 @@ public function testXMLValidConstraintFalse()
         $constraint->evaluate(false);
     }
 
-    public function testXMLValidConstraintInt()
+    public function testXMLValidConstraintInt(): void
     {
         $this->expectException(
             'PHPUnit\Framework\ExpectationFailedException'
@@ -75,7 +77,7 @@ public function testXMLValidConstraintInt()
         $constraint->evaluate(1);
     }
 
-    public function testXMLValidConstraintInvalidXML()
+    public function testXMLValidConstraintInvalidXML(): void
     {
         $this->expectException(
             'PHPUnit\Framework\ExpectationFailedException'
@@ -88,7 +90,7 @@ public function testXMLValidConstraintInvalidXML()
         $constraint->evaluate('<a></b>');
     }
 
-    public function testXMLValidConstraintNotMatchingXML()
+    public function testXMLValidConstraintNotMatchingXML(): void
     {
         $this->expectException(
             'PHPUnit\Framework\ExpectationFailedException'
@@ -101,7 +103,7 @@ public function testXMLValidConstraintNotMatchingXML()
         $constraint->evaluate('<a></a>');
     }
 
-    public function testXMLValidConstraintNull()
+    public function testXMLValidConstraintNull(): void
     {
         $this->expectException(
             'PHPUnit\Framework\ExpectationFailedException'
@@ -114,7 +116,7 @@ public function testXMLValidConstraintNull()
         $constraint->evaluate(null);
     }
 
-    public function testXMLValidConstraintObject()
+    public function testXMLValidConstraintObject(): void
     {
         $this->expectException(
             'PHPUnit\Framework\ExpectationFailedException'
@@ -146,10 +148,10 @@ private function getAssetsDir()
     /**
      * @param string $pattern
      */
-    private function expectExceptionMessageRegex($pattern)
+    private function expectExceptionMessageRegex($pattern): void
     {
         if (method_exists($this, 'expectExceptionMessageRegExp')) {
-            $this->expectExceptionMessageRegExp($pattern);
+            $this->expectExceptionMessageMatches($pattern);
         } elseif (method_exists($this, 'expectExceptionMessageMatches')) {
             $this->expectExceptionMessageMatches($pattern);
         } elseif (method_exists($this, 'expectDeprecationMessageMatches')) {