diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6594e5d7..e618855e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,7 +19,7 @@ jobs:
         strategy:
             matrix:
                 php-version:
-                    - '7.4'
+                    - '8.1'
 
         steps:
             -
@@ -52,7 +52,7 @@ jobs:
         strategy:
             matrix:
                 php-version:
-                    - '7.4'
+                    - '8.1'
 
         steps:
             -
@@ -85,8 +85,10 @@ jobs:
         strategy:
             matrix:
                 php-version:
-                    - '7.4'
-                    - '8.0'
+                    - '8.1'
+                    - '8.2'
+                    - '8.3'
+                    - '8.4'
 
         steps:
             -
diff --git a/.gitignore b/.gitignore
index e87ba04f..9844e1a0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,7 @@
 /tests/Assets/workspace
 /phpbench.json
 /composer.lock
-/.php_cs.cache
 /stubs
 /.vscode
-.php_cs.cache
\ No newline at end of file
+.phpunit.result.cache
+.php-cs-fixer.cache
diff --git a/.php_cs.dist b/.php-cs-fixer.dist.php
similarity index 88%
rename from .php_cs.dist
rename to .php-cs-fixer.dist.php
index 2820b890..2c205486 100644
--- a/.php_cs.dist
+++ b/.php-cs-fixer.dist.php
@@ -8,7 +8,8 @@
     ])
 ;
 
-return PhpCsFixer\Config::create()
+return (new PhpCsFixer\Config())
+    ->setRiskyAllowed(true)
     ->setRules([
         '@PSR2' => true,
         'no_unused_imports' => true,
diff --git a/composer.json b/composer.json
index 2f4e1cb9..d79d7583 100644
--- a/composer.json
+++ b/composer.json
@@ -10,15 +10,15 @@
         }
     ],
     "require": {
-        "php": "^7.3 || ^8.0"
+        "php": "^8.1"
     },
     "require-dev": {
         "ergebnis/composer-normalize": "^2.0",
-        "friendsofphp/php-cs-fixer": "^2.17",
-        "infection/infection": "^0.18.0",
-        "phpstan/phpstan": "~0.12.0",
-        "phpunit/phpunit": "^9.0",
-        "symfony/var-dumper": "^6.1"
+        "phpstan/phpstan": "^2.0",
+        "phpunit/phpunit": "^10.0",
+        "symfony/var-dumper": "^6.0|^7.1",
+        "infection/infection": "^0.29.0",
+        "friendsofphp/php-cs-fixer": "^3.91"
     },
     "extra": {
         "branch-alias": {
@@ -40,7 +40,7 @@
     "scripts": {
         "integrate": [
             "./vendor/bin/phpunit",
-            "./vendor/bin/phpstan analyze",
+            "./vendor/bin/phpstan analyze --memory-limit=-1",
             "./vendor/bin/php-cs-fixer fix --allow-risky=yes"
         ]
     },
diff --git a/lib/Resolver.php b/lib/Resolver.php
index 73a68fc8..0be9c486 100644
--- a/lib/Resolver.php
+++ b/lib/Resolver.php
@@ -118,11 +118,7 @@ public function resolve(array $config): array
 
         if ($diff = array_diff(array_keys($config), $allowedKeys)) {
             $this->throwOrLogError(
-                new InvalidMap(sprintf(
-                    'Key(s) "%s" are not known, known keys: "%s"',
-                    implode('", "', ($diff)),
-                    implode('", "', $allowedKeys)
-                ))
+                UnknownKeys::fromKeysAndAllowedKeys(array_values($diff), $allowedKeys)
             );
 
             $config = $this->removeKeys($config, $diff);
@@ -227,12 +223,12 @@ public function errors(): ResolverErrors
     }
 
     /**
-     * @return array<string>
+     * @return list<string>
      */
     private function resolveAllowedKeys(): array
     {
         $allowedKeys = array_merge(array_keys($this->defaults), $this->required);
-        return $allowedKeys;
+        return array_values($allowedKeys);
     }
 
     private function throwOrLogError(InvalidMap $error): void
diff --git a/lib/UnknownKeys.php b/lib/UnknownKeys.php
new file mode 100644
index 00000000..3078eae4
--- /dev/null
+++ b/lib/UnknownKeys.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace Phpactor\MapResolver;
+
+class UnknownKeys extends InvalidMap
+{
+    /**
+     * @param list<string> $allowedKeys
+     * @param list<string> $keys
+     */
+    public function __construct(string $message, private array $keys, private array $allowedKeys)
+    {
+        parent::__construct($message);
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function additionalKeys(): array
+    {
+        return $this->keys;
+    }
+
+    /**
+     * @return list<string>
+     */
+    public function allowedKeys(): array
+    {
+        return $this->allowedKeys;
+    }
+
+    /**
+     * @param list<string> $allowedKeys
+     * @param list<string> $diff
+     */
+    public static function fromKeysAndAllowedKeys(array $diff, array $allowedKeys): self
+    {
+        return new self(sprintf(
+            'Key(s) "%s" are not known, known keys: "%s"',
+            implode('", "', ($diff)),
+            implode('", "', $allowedKeys),
+        ), $diff, $allowedKeys);
+    }
+}
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index cb7f36fd..364905f7 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -1,7 +1,2 @@
 parameters:
 	ignoreErrors:
-		-
-			message: "#^Method Phpactor\\\\MapResolver\\\\Resolver\\:\\:resolveDescriptions\\(\\) should return array\\<string, string\\> but returns array\\<int\\|string, string\\|false\\|null\\>\\.$#"
-			count: 1
-			path: lib/Resolver.php
-
diff --git a/tests/Unit/ResolverTest.php b/tests/Unit/ResolverTest.php
index 50e31dd1..65042e2f 100644
--- a/tests/Unit/ResolverTest.php
+++ b/tests/Unit/ResolverTest.php
@@ -5,6 +5,7 @@
 use PHPUnit\Framework\TestCase;
 use Phpactor\MapResolver\Definition;
 use Phpactor\MapResolver\InvalidMap;
+use Phpactor\MapResolver\UnknownKeys;
 use Phpactor\MapResolver\Resolver;
 use stdClass;
 
@@ -25,12 +26,18 @@ public function testThrowsExceptionOnUnknownKey(): void
         $this->expectException(InvalidMap::class);
         $this->expectExceptionMessage('Key(s) "three" are not known');
 
-        $resolver = new Resolver();
-        $resolver->setDefaults([
-            'one' => 1,
-            'two' => 2,
-        ]);
-        $resolver->resolve(['three' => 3]);
+        try {
+            $resolver = new Resolver();
+            $resolver->setDefaults([
+                'one' => 1,
+                'two' => 2,
+            ]);
+            $resolver->resolve(['three' => 3]);
+        } catch (UnknownKeys $e) {
+            self::assertEquals(['three'], $e->additionalKeys());
+            self::assertEquals(['one', 'two'], $e->allowedKeys());
+            throw $e;
+        }
     }
 
     public function testIgnoresUnknownKey(): void