diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index 77c8f42..49c2ea4 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -2,4 +2,8 @@
 
 require_once 'vendor/autoload.php';
 
-return CodingStandards\Factory::createPhpCsFixerConfig(__DIR__);
+return CodingStandards\Factory::createPhpCsFixerConfig(__DIR__, [
+    'rules' => [
+        'nullable_type_declaration' => ['syntax' => 'union']
+    ]
+]);
diff --git a/composer.json b/composer.json
index 95bafbb..616b383 100644
--- a/composer.json
+++ b/composer.json
@@ -2,11 +2,19 @@
   "name": "worldia/instrumentation-bundle",
   "type": "symfony-bundle",
   "license": "MIT",
-  "keywords": ["instrumentation", "tracing", "metrics", "open-telemetry", "prometheus"],
-  "authors": [{
-    "name": "Worldia developers",
-    "email": "developers@worldia.com"
-  }],
+  "keywords": [
+    "instrumentation",
+    "tracing",
+    "metrics",
+    "open-telemetry",
+    "prometheus"
+  ],
+  "authors": [
+    {
+      "name": "Worldia developers",
+      "email": "developers@worldia.com"
+    }
+  ],
   "require": {
     "monolog/monolog": "^2.0",
     "nyholm/dsn": "^2.0",
@@ -20,11 +28,10 @@
   "require-dev": {
     "doctrine/dbal": "^3.0",
     "friends-of-phpspec/phpspec-expect": "^4.0",
-    "open-telemetry/sdk-contrib": "^1.0@dev",
     "open-telemetry/transport-grpc": "^1.0",
     "open-telemetry/gen-otlp-protobuf": "^1.0",
     "php-http/httplug": "^2.3",
-    "phpspec/phpspec": "^7.2",
+    "phpspec/phpspec": "^7.5",
     "phpstan/phpstan": "^1.4",
     "symfony/framework-bundle": "*",
     "symfony/http-client": "*",
diff --git a/spec/Baggage/Propagation/Http/BaggageHeaderProviderSpec.php b/spec/Baggage/Propagation/Http/BaggageHeaderProviderSpec.php
index ba48a27..fd3eb3b 100644
--- a/spec/Baggage/Propagation/Http/BaggageHeaderProviderSpec.php
+++ b/spec/Baggage/Propagation/Http/BaggageHeaderProviderSpec.php
@@ -14,7 +14,7 @@
 
 class BaggageHeaderProviderSpec extends ObjectBehavior
 {
-    private ?ScopeInterface $scope = null;
+    private ScopeInterface|null $scope = null;
 
     public function let()
     {
diff --git a/spec/Baggage/Propagation/Messenger/BaggageStampSpec.php b/spec/Baggage/Propagation/Messenger/BaggageStampSpec.php
index eec21aa..b62b928 100644
--- a/spec/Baggage/Propagation/Messenger/BaggageStampSpec.php
+++ b/spec/Baggage/Propagation/Messenger/BaggageStampSpec.php
@@ -15,7 +15,7 @@
 
 class BaggageStampSpec extends ObjectBehavior
 {
-    private ?ScopeInterface $scope = null;
+    private ScopeInterface|null $scope = null;
 
     public function let()
     {
diff --git a/spec/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriberSpec.php b/spec/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriberSpec.php
index 4dcaa2d..505cf13 100644
--- a/spec/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriberSpec.php
+++ b/spec/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriberSpec.php
@@ -146,7 +146,7 @@ private function createConsoleCommandEvent(Command|null $command = null): Consol
         return new ConsoleCommandEvent($command, new ArrayInput([]), new NullOutput());
     }
 
-    private function createConsoleErrorEvent(Command|null $command = null): ConsoleErrorEvent
+    private function createConsoleErrorEvent(): ConsoleErrorEvent
     {
         return new ConsoleErrorEvent(new ArrayInput([]), new NullOutput(), new \Exception());
     }
diff --git a/src/Baggage/Propagation/ContextInitializer.php b/src/Baggage/Propagation/ContextInitializer.php
index fc9b978..c05c3f4 100644
--- a/src/Baggage/Propagation/ContextInitializer.php
+++ b/src/Baggage/Propagation/ContextInitializer.php
@@ -17,7 +17,7 @@
 
 final class ContextInitializer
 {
-    public static function fromRequest(Request $request): ?ScopeInterface
+    public static function fromRequest(Request $request): ScopeInterface|null
     {
         if (!$baggage = $request->headers->get(BaggagePropagator::BAGGAGE)) {
             return null;
@@ -26,7 +26,7 @@ public static function fromRequest(Request $request): ?ScopeInterface
         return static::activateContext($baggage);
     }
 
-    public static function fromMessage(Envelope $envelope): ?ScopeInterface
+    public static function fromMessage(Envelope $envelope): ScopeInterface|null
     {
         /** @var BaggageStamp|null $stamp */
         $stamp = $envelope->last(BaggageStamp::class);
@@ -38,7 +38,7 @@ public static function fromMessage(Envelope $envelope): ?ScopeInterface
         return static::activateContext($stamp->getBaggage());
     }
 
-    public static function fromW3CHeader(string $header): ?ScopeInterface
+    public static function fromW3CHeader(string $header): ScopeInterface|null
     {
         return static::activateContext($header);
     }
diff --git a/src/Baggage/Propagation/EventSubscriber/MessengerEventSubscriber.php b/src/Baggage/Propagation/EventSubscriber/MessengerEventSubscriber.php
index 995e710..755d19a 100644
--- a/src/Baggage/Propagation/EventSubscriber/MessengerEventSubscriber.php
+++ b/src/Baggage/Propagation/EventSubscriber/MessengerEventSubscriber.php
@@ -18,7 +18,7 @@
 
 class MessengerEventSubscriber implements EventSubscriberInterface
 {
-    private ?ScopeInterface $scope = null;
+    private ScopeInterface|null $scope = null;
 
     public static function getSubscribedEvents(): array
     {
diff --git a/src/Baggage/Propagation/EventSubscriber/RequestEventSubscriber.php b/src/Baggage/Propagation/EventSubscriber/RequestEventSubscriber.php
index 75bf55a..1309804 100644
--- a/src/Baggage/Propagation/EventSubscriber/RequestEventSubscriber.php
+++ b/src/Baggage/Propagation/EventSubscriber/RequestEventSubscriber.php
@@ -17,7 +17,7 @@
 
 class RequestEventSubscriber implements EventSubscriberInterface
 {
-    private ?ScopeInterface $scope = null;
+    private ScopeInterface|null $scope = null;
 
     public static function getSubscribedEvents(): array
     {
diff --git a/src/Bridge/GoogleCloud/Logging/Formatter/StdOutFormatter.php b/src/Bridge/GoogleCloud/Logging/Formatter/StdOutFormatter.php
index 8fddc35..7e8ec7a 100644
--- a/src/Bridge/GoogleCloud/Logging/Formatter/StdOutFormatter.php
+++ b/src/Bridge/GoogleCloud/Logging/Formatter/StdOutFormatter.php
@@ -101,7 +101,7 @@ protected function normalizeException(\Throwable $e, int $depth = 0): array
      *
      * @param array<mixed> $trace The stack trace returned from Exception::getTrace()
      */
-    private static function getFunctionNameForReport(?array $trace = null): string
+    private static function getFunctionNameForReport(array|null $trace = null): string
     {
         if (null === $trace) {
             return '<unknown function>';
diff --git a/src/Health/Controller/Endpoint.php b/src/Health/Controller/Endpoint.php
index cf57368..e0d97c6 100644
--- a/src/Health/Controller/Endpoint.php
+++ b/src/Health/Controller/Endpoint.php
@@ -31,7 +31,7 @@ public static function getProvidedMetrics(): array
     /**
      * @param iterable<HealtcheckInterface> $checks
      */
-    public function __construct(private ResourceInfo $resourceInfo, private iterable $checks, private ?RegistryInterface $registry = null, private ?Profiler $profiler = null)
+    public function __construct(private ResourceInfo $resourceInfo, private iterable $checks, private RegistryInterface|null $registry = null, private Profiler|null $profiler = null)
     {
     }
 
diff --git a/src/Health/HealtcheckInterface.php b/src/Health/HealtcheckInterface.php
index 9b50a92..4cf365f 100644
--- a/src/Health/HealtcheckInterface.php
+++ b/src/Health/HealtcheckInterface.php
@@ -17,14 +17,14 @@ interface HealtcheckInterface
 
     public function getName(): string;
 
-    public function getDescription(): ?string;
+    public function getDescription(): string|null;
 
     /**
      * Contextual information about the status.
      * Should be returned when the check is failing to give additional
      * information about the reason for the current status.
      */
-    public function getStatusMessage(): ?string;
+    public function getStatusMessage(): string|null;
 
     /**
      * @return string One of the HealtcheckInterface constants
diff --git a/src/Http/TracedResponse.php b/src/Http/TracedResponse.php
index e8b42d9..988768f 100644
--- a/src/Http/TracedResponse.php
+++ b/src/Http/TracedResponse.php
@@ -21,7 +21,7 @@
 
 class TracedResponse implements ResponseInterface, StreamableInterface
 {
-    private ?string $content = null;
+    private string|null $content = null;
     /** @var resource|null */
     private $stream;
 
@@ -110,7 +110,7 @@ public function cancel(): void
         }
     }
 
-    public function getInfo(?string $type = null): mixed
+    public function getInfo(string|null $type = null): mixed
     {
         return $this->response->getInfo($type);
     }
@@ -139,7 +139,7 @@ public function toStream(bool $throw = true)
      *
      * @internal
      */
-    public static function stream(HttpClientInterface $client, iterable $responses, ?float $timeout): \Generator
+    public static function stream(HttpClientInterface $client, iterable $responses, float|null $timeout): \Generator
     {
         $wrappedResponses = [];
         $traceableMap = new \SplObjectStorage();
diff --git a/src/Http/TracingHttpClient.php b/src/Http/TracingHttpClient.php
index 552b401..6da6f49 100644
--- a/src/Http/TracingHttpClient.php
+++ b/src/Http/TracingHttpClient.php
@@ -39,8 +39,8 @@ final class TracingHttpClient implements HttpClientInterface
      */
     public function __construct(
         HttpClientInterface|array|null $client = null,
-        ?ClientRequestOperationNameResolverInterface $operationNameResolver = null,
-        ?ClientRequestAttributeProviderInterface $attributeProvider = null,
+        ClientRequestOperationNameResolverInterface|null $operationNameResolver = null,
+        ClientRequestAttributeProviderInterface|null $attributeProvider = null,
         int $maxHostConnections = 6,
         int $maxPendingPushes = 50
     ) {
@@ -61,7 +61,7 @@ public function __construct(
      *
      * @return array<string>
      */
-    protected function getExtraSpanAttributes(?array $attributes): array
+    protected function getExtraSpanAttributes(array|null $attributes): array
     {
         $attributes = $attributes ?: $_SERVER['OTEL_PHP_HTTP_SPAN_ATTRIBUTES'] ?? [];
 
@@ -140,7 +140,7 @@ public function request(string $method, string $url, array $options = []): Respo
         return new TracedResponse($this->client->request($method, $url, $options), $span);
     }
 
-    public function stream(ResponseInterface|iterable $responses, ?float $timeout = null): ResponseStreamInterface
+    public function stream(ResponseInterface|iterable $responses, float|null $timeout = null): ResponseStreamInterface
     {
         if ($responses instanceof ResponseInterface) {
             $responses = [$responses];
diff --git a/src/Logging/Formatter/JsonFormatter.php b/src/Logging/Formatter/JsonFormatter.php
index bd02ccb..9c9d26d 100644
--- a/src/Logging/Formatter/JsonFormatter.php
+++ b/src/Logging/Formatter/JsonFormatter.php
@@ -14,7 +14,7 @@
 
 class JsonFormatter extends BaseJsonFormatter
 {
-    private ?int $lengthLimit = null;
+    private int|null $lengthLimit = null;
 
     public function format(array $record): string
     {
diff --git a/src/Logging/Logging.php b/src/Logging/Logging.php
index 6506b5a..6953073 100644
--- a/src/Logging/Logging.php
+++ b/src/Logging/Logging.php
@@ -15,9 +15,9 @@
 
 class Logging
 {
-    private static ?LoggerInterface $logger = null;
+    private static LoggerInterface|null $logger = null;
 
-    public function __construct(?LoggerInterface $logger)
+    public function __construct(LoggerInterface|null $logger)
     {
         if (self::$logger) {
             return;
diff --git a/src/Metrics/Controller/Endpoint.php b/src/Metrics/Controller/Endpoint.php
index c0eaccd..808a8ff 100644
--- a/src/Metrics/Controller/Endpoint.php
+++ b/src/Metrics/Controller/Endpoint.php
@@ -16,7 +16,7 @@
 
 final class Endpoint
 {
-    public function __construct(private CollectorRegistry $registry, private ?Profiler $profiler = null)
+    public function __construct(private CollectorRegistry $registry, private Profiler|null $profiler = null)
     {
     }
 
diff --git a/src/Metrics/EventSubscriber/RequestEventSubscriber.php b/src/Metrics/EventSubscriber/RequestEventSubscriber.php
index 92d9f3d..c906771 100644
--- a/src/Metrics/EventSubscriber/RequestEventSubscriber.php
+++ b/src/Metrics/EventSubscriber/RequestEventSubscriber.php
@@ -49,7 +49,7 @@ public static function getProvidedMetrics(): array
     /**
      * @param array<string> $blacklist
      */
-    public function __construct(private RegistryInterface $registry, private array $blacklist, private ?MainSpanContextInterface $mainSpanContext = null)
+    public function __construct(private RegistryInterface $registry, private array $blacklist, private MainSpanContextInterface|null $mainSpanContext = null)
     {
     }
 
diff --git a/src/Metrics/Meter.php b/src/Metrics/Meter.php
index 3bdaeec..86426c1 100644
--- a/src/Metrics/Meter.php
+++ b/src/Metrics/Meter.php
@@ -37,7 +37,7 @@ public function __construct(
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#counter-creation
      */
-    public function createCounter(string $name, ?string $unit = null, ?string $description = null, array $advisory = []): CounterInterface
+    public function createCounter(string $name, string|null $unit = null, string|null $description = null, array $advisory = []): CounterInterface
     {
         return new CounterAdapter($name, $description ?: '', $this->collectorRegistry);
     }
@@ -56,7 +56,7 @@ public function createCounter(string $name, ?string $unit = null, ?string $descr
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#asynchronous-counter-creation
      */
-    public function createObservableCounter(string $name, ?string $unit = null, ?string $description = null, $advisory = [], callable ...$callbacks): ObservableCounterInterface
+    public function createObservableCounter(string $name, string|null $unit = null, string|null $description = null, $advisory = [], callable ...$callbacks): ObservableCounterInterface
     {
         throw new \LogicException(sprintf('Method %s is not implemented', __METHOD__));
     }
@@ -74,7 +74,7 @@ public function createObservableCounter(string $name, ?string $unit = null, ?str
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#histogram-creation
      */
-    public function createHistogram(string $name, ?string $unit = null, ?string $description = null, array $advisory = []): HistogramInterface
+    public function createHistogram(string $name, string|null $unit = null, string|null $description = null, array $advisory = []): HistogramInterface
     {
         return new HistogramAdapter($name, $description ?: '', $this->collectorRegistry);
     }
@@ -93,7 +93,7 @@ public function createHistogram(string $name, ?string $unit = null, ?string $des
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#asynchronous-gauge-creation
      */
-    public function createObservableGauge(string $name, ?string $unit = null, ?string $description = null, $advisory = [], callable ...$callbacks): ObservableGaugeInterface
+    public function createObservableGauge(string $name, string|null $unit = null, string|null $description = null, $advisory = [], callable ...$callbacks): ObservableGaugeInterface
     {
         throw new \LogicException(sprintf('Method %s is not implemented', __METHOD__));
     }
@@ -110,7 +110,7 @@ public function createObservableGauge(string $name, ?string $unit = null, ?strin
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#updowncounter-creation
      */
-    public function createUpDownCounter(string $name, ?string $unit = null, ?string $description = null, array $advisory = []): UpDownCounterInterface
+    public function createUpDownCounter(string $name, string|null $unit = null, string|null $description = null, array $advisory = []): UpDownCounterInterface
     {
         return new UpDownCounterAdapter($name, $description ?: '', $this->collectorRegistry);
     }
@@ -129,7 +129,7 @@ public function createUpDownCounter(string $name, ?string $unit = null, ?string
      *
      * @see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#asynchronous-updowncounter-creation
      */
-    public function createObservableUpDownCounter(string $name, ?string $unit = null, ?string $description = null, $advisory = [], callable ...$callbacks): ObservableUpDownCounterInterface
+    public function createObservableUpDownCounter(string $name, string|null $unit = null, string|null $description = null, $advisory = [], callable ...$callbacks): ObservableUpDownCounterInterface
     {
         throw new \LogicException(sprintf('Method %s is not implemented', __METHOD__));
     }
diff --git a/src/Metrics/MetricDefinition.php b/src/Metrics/MetricDefinition.php
index 4c3b0ea..889fb86 100644
--- a/src/Metrics/MetricDefinition.php
+++ b/src/Metrics/MetricDefinition.php
@@ -24,7 +24,7 @@ public function __construct(
         private string $type,
         private string $help,
         private array $labels = [],
-        private ?array $buckets = null
+        private array|null $buckets = null
     ) {
     }
 
@@ -59,7 +59,7 @@ public function getHelp(): string
     /**
      * @return array<int|float>
      */
-    public function getBuckets(): ?array
+    public function getBuckets(): array|null
     {
         return $this->buckets;
     }
diff --git a/src/Metrics/Metrics.php b/src/Metrics/Metrics.php
index e5e04d8..29758ab 100644
--- a/src/Metrics/Metrics.php
+++ b/src/Metrics/Metrics.php
@@ -11,7 +11,7 @@
 
 final class Metrics
 {
-    private static ?RegistryInterface $registry = null;
+    private static RegistryInterface|null $registry = null;
 
     public static function getRegistry(): RegistryInterface
     {
diff --git a/src/Metrics/Storage/HostnamePrefixedRedisFactory.php b/src/Metrics/Storage/HostnamePrefixedRedisFactory.php
index a3985f5..1a63699 100644
--- a/src/Metrics/Storage/HostnamePrefixedRedisFactory.php
+++ b/src/Metrics/Storage/HostnamePrefixedRedisFactory.php
@@ -12,7 +12,7 @@
 
 final class HostnamePrefixedRedisFactory
 {
-    public function __construct(private ?RedisPrefixProvider $redisPrefixProvider)
+    public function __construct(private RedisPrefixProvider|null $redisPrefixProvider)
     {
     }
 
diff --git a/src/Metrics/Storage/RedisPrefixProvider.php b/src/Metrics/Storage/RedisPrefixProvider.php
index 93a2597..54110ff 100644
--- a/src/Metrics/Storage/RedisPrefixProvider.php
+++ b/src/Metrics/Storage/RedisPrefixProvider.php
@@ -9,7 +9,7 @@
 
 class RedisPrefixProvider
 {
-    protected static ?RedisPrefixProvider $instance = null;
+    protected static RedisPrefixProvider|null $instance = null;
     protected string $prefix;
 
     protected function __construct()
diff --git a/src/Semantics/Attribute/ServerRequestAttributeProvider.php b/src/Semantics/Attribute/ServerRequestAttributeProvider.php
index 3f78e25..6e7392d 100644
--- a/src/Semantics/Attribute/ServerRequestAttributeProvider.php
+++ b/src/Semantics/Attribute/ServerRequestAttributeProvider.php
@@ -17,7 +17,7 @@ class ServerRequestAttributeProvider implements ServerRequestAttributeProviderIn
     /**
      * @param array<string> $capturedHeaders
      */
-    public function __construct(private ?string $serverName = null, private array $capturedHeaders = [])
+    public function __construct(private string|null $serverName = null, private array $capturedHeaders = [])
     {
     }
 
diff --git a/src/Semantics/OperationName/CommandOperationNameResolver.php b/src/Semantics/OperationName/CommandOperationNameResolver.php
index a1679c6..ce7d7ed 100644
--- a/src/Semantics/OperationName/CommandOperationNameResolver.php
+++ b/src/Semantics/OperationName/CommandOperationNameResolver.php
@@ -13,7 +13,7 @@
 
 class CommandOperationNameResolver implements CommandOperationNameResolverInterface
 {
-    public function getOperationName(?Command $command): string
+    public function getOperationName(Command|null $command): string
     {
         $name = 'unknown-command';
 
diff --git a/src/Semantics/OperationName/CommandOperationNameResolverInterface.php b/src/Semantics/OperationName/CommandOperationNameResolverInterface.php
index 14d248f..6b83796 100644
--- a/src/Semantics/OperationName/CommandOperationNameResolverInterface.php
+++ b/src/Semantics/OperationName/CommandOperationNameResolverInterface.php
@@ -16,5 +16,5 @@ interface CommandOperationNameResolverInterface
     /**
      * @return string&non-empty-string
      */
-    public function getOperationName(?Command $command): string;
+    public function getOperationName(Command|null $command): string;
 }
diff --git a/src/Semantics/OperationName/RoutePath/RouteCacheWarmer.php b/src/Semantics/OperationName/RoutePath/RouteCacheWarmer.php
index 9373140..134f45e 100644
--- a/src/Semantics/OperationName/RoutePath/RouteCacheWarmer.php
+++ b/src/Semantics/OperationName/RoutePath/RouteCacheWarmer.php
@@ -23,7 +23,7 @@ public function isOptional(): bool
         return true;
     }
 
-    public function warmUp(string $cacheDir, ?string $buildDir = null): array
+    public function warmUp(string $cacheDir, string|null $buildDir = null): array
     {
         $routes = [];
         foreach ($this->router->getRouteCollection() as $name => $route) {
diff --git a/src/Semantics/OperationName/RoutePath/RoutePathResolver.php b/src/Semantics/OperationName/RoutePath/RoutePathResolver.php
index b3a228a..fc9c1a6 100644
--- a/src/Semantics/OperationName/RoutePath/RoutePathResolver.php
+++ b/src/Semantics/OperationName/RoutePath/RoutePathResolver.php
@@ -13,7 +13,7 @@ public function __construct(private RouteCacheWarmer $routeCacheWarmer, private
     {
     }
 
-    public function resolve(string $routeName): ?string
+    public function resolve(string $routeName): string|null
     {
         $routePathCacheFilename = $this->routeCacheWarmer->getCacheFile($this->cacheDir);
 
diff --git a/src/Semantics/OperationName/RoutePath/RoutePathResolverInterface.php b/src/Semantics/OperationName/RoutePath/RoutePathResolverInterface.php
index 5917d12..0b5f999 100644
--- a/src/Semantics/OperationName/RoutePath/RoutePathResolverInterface.php
+++ b/src/Semantics/OperationName/RoutePath/RoutePathResolverInterface.php
@@ -9,5 +9,5 @@
 
 interface RoutePathResolverInterface
 {
-    public function resolve(string $routeName): ?string;
+    public function resolve(string $routeName): string|null;
 }
diff --git a/src/Semantics/ResourceInfoProvider.php b/src/Semantics/ResourceInfoProvider.php
index d33231a..882edc9 100644
--- a/src/Semantics/ResourceInfoProvider.php
+++ b/src/Semantics/ResourceInfoProvider.php
@@ -15,7 +15,7 @@
 
 class ResourceInfoProvider implements ResourceInfoProviderInterface
 {
-    private ?ResourceInfo $info = null;
+    private ResourceInfo|null $info = null;
 
     /**
      * @param array<string,string> $attributes
diff --git a/src/Tracing/Instrumentation/EventSubscriber/AddUserEventSubscriber.php b/src/Tracing/Instrumentation/EventSubscriber/AddUserEventSubscriber.php
index 5f927e5..46a5420 100644
--- a/src/Tracing/Instrumentation/EventSubscriber/AddUserEventSubscriber.php
+++ b/src/Tracing/Instrumentation/EventSubscriber/AddUserEventSubscriber.php
@@ -30,7 +30,7 @@ public static function getSubscribedEvents(): array
         ];
     }
 
-    public function __construct(private MainSpanContextInterface $mainSpanContext, private ?TokenStorageInterface $tokenStorage = null)
+    public function __construct(private MainSpanContextInterface $mainSpanContext, private TokenStorageInterface|null $tokenStorage = null)
     {
     }
 
@@ -68,7 +68,7 @@ private function getRoles(UserInterface|\Stringable|string $user): array
         return [];
     }
 
-    private function getUsername(UserInterface|\Stringable|string $user): ?string
+    private function getUsername(UserInterface|\Stringable|string $user): string|null
     {
         if ($user instanceof UserInterface) {
             if (method_exists($user, 'getUserIdentifier')) {
diff --git a/src/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriber.php b/src/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriber.php
index 027c09b..a432984 100644
--- a/src/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriber.php
+++ b/src/Tracing/Instrumentation/EventSubscriber/CommandEventSubscriber.php
@@ -26,8 +26,8 @@ class CommandEventSubscriber implements EventSubscriberInterface
 {
     use TracerAwareTrait;
 
-    private ?SpanInterface $span = null;
-    private ?ScopeInterface $scope = null;
+    private SpanInterface|null $span = null;
+    private ScopeInterface|null $scope = null;
 
     public static function getSubscribedEvents(): array
     {
diff --git a/src/Tracing/Instrumentation/EventSubscriber/RequestEventSubscriber.php b/src/Tracing/Instrumentation/EventSubscriber/RequestEventSubscriber.php
index 6ea9641..5215b8d 100644
--- a/src/Tracing/Instrumentation/EventSubscriber/RequestEventSubscriber.php
+++ b/src/Tracing/Instrumentation/EventSubscriber/RequestEventSubscriber.php
@@ -29,8 +29,8 @@ class RequestEventSubscriber implements EventSubscriberInterface
 {
     use TracerAwareTrait;
 
-    private ?SpanInterface $serverSpan = null;
-    private ?ScopeInterface $serverScope = null;
+    private SpanInterface|null $serverSpan = null;
+    private ScopeInterface|null $serverScope = null;
 
     /**
      * @var \SplObjectStorage<Request,SpanInterface>
diff --git a/src/Tracing/Instrumentation/MainSpanContext.php b/src/Tracing/Instrumentation/MainSpanContext.php
index eed691b..d6a6a9c 100644
--- a/src/Tracing/Instrumentation/MainSpanContext.php
+++ b/src/Tracing/Instrumentation/MainSpanContext.php
@@ -14,8 +14,8 @@
 
 final class MainSpanContext implements MainSpanContextInterface
 {
-    private ?SpanInterface $mainSpan = null;
-    private ?string $operationName = null;
+    private SpanInterface|null $mainSpan = null;
+    private string|null $operationName = null;
 
     public function setCurrent(): void
     {
@@ -36,12 +36,12 @@ public function setMainSpan(SpanInterface $span): void
         $this->mainSpan = $span;
     }
 
-    public function getOperationName(): ?string
+    public function getOperationName(): string|null
     {
         return $this->operationName;
     }
 
-    public function setOperationName(?string $name): void
+    public function setOperationName(string|null $name): void
     {
         $this->operationName = $name;
     }
diff --git a/src/Tracing/Instrumentation/MainSpanContextInterface.php b/src/Tracing/Instrumentation/MainSpanContextInterface.php
index e77532a..9ff3a27 100644
--- a/src/Tracing/Instrumentation/MainSpanContextInterface.php
+++ b/src/Tracing/Instrumentation/MainSpanContextInterface.php
@@ -19,7 +19,7 @@ public function getMainSpan(): SpanInterface;
 
     public function setMainSpan(SpanInterface $span): void;
 
-    public function getOperationName(): ?string;
+    public function getOperationName(): string|null;
 
-    public function setOperationName(?string $name): void;
+    public function setOperationName(string|null $name): void;
 }
diff --git a/src/Tracing/Instrumentation/TracerAwareTrait.php b/src/Tracing/Instrumentation/TracerAwareTrait.php
index 061b6fc..646b898 100644
--- a/src/Tracing/Instrumentation/TracerAwareTrait.php
+++ b/src/Tracing/Instrumentation/TracerAwareTrait.php
@@ -38,7 +38,7 @@ protected function startSpan(string $name, array $attributes = []): SpanInterfac
      * @param array<string,string>    $attributes
      * @param SpanKind::KIND_*        $kind
      */
-    protected function traceFunction(string $name, array $attributes, callable $callback, ?Context $parentContext = null, ?int $kind = null): mixed
+    protected function traceFunction(string $name, array $attributes, callable $callback, Context|null $parentContext = null, int|null $kind = null): mixed
     {
         $span = $this->getTracer()
             ->spanBuilder($name) // @phpstan-ignore-line
diff --git a/src/Tracing/Propagation/ContextInitializer.php b/src/Tracing/Propagation/ContextInitializer.php
index c338a9f..ce46ee7 100644
--- a/src/Tracing/Propagation/ContextInitializer.php
+++ b/src/Tracing/Propagation/ContextInitializer.php
@@ -17,7 +17,7 @@
 
 final class ContextInitializer
 {
-    public static function fromRequest(Request $request): ?ScopeInterface
+    public static function fromRequest(Request $request): ScopeInterface|null
     {
         if (!$traceparent = $request->headers->get(TraceContextPropagator::TRACEPARENT)) {
             return null;
@@ -28,7 +28,7 @@ public static function fromRequest(Request $request): ?ScopeInterface
         return static::activateContext($traceparent, $tracestate);
     }
 
-    public static function fromMessage(Envelope $envelope): ?ScopeInterface
+    public static function fromMessage(Envelope $envelope): ScopeInterface|null
     {
         /** @var TraceContextStamp|null $stamp */
         $stamp = $envelope->last(TraceContextStamp::class);
@@ -45,7 +45,7 @@ public static function fromW3CHeader(string $header): ScopeInterface
         return static::activateContext($header);
     }
 
-    public static function activateContext(string $parent, ?string $state = null): ScopeInterface
+    public static function activateContext(string $parent, string|null $state = null): ScopeInterface
     {
         $context = TraceContextPropagator::getInstance()->extract(array_filter([
             TraceContextPropagator::TRACEPARENT => $parent,
diff --git a/src/Tracing/Propagation/Doctrine/TraceContextInfoProvider.php b/src/Tracing/Propagation/Doctrine/TraceContextInfoProvider.php
index b1e0051..ceac5c2 100644
--- a/src/Tracing/Propagation/Doctrine/TraceContextInfoProvider.php
+++ b/src/Tracing/Propagation/Doctrine/TraceContextInfoProvider.php
@@ -22,9 +22,9 @@ class TraceContextInfoProvider implements TraceContextInfoProviderInterface
     /**
      * @var array<string,string>
      */
-    private ?array $info = null;
+    private array|null $info = null;
 
-    public function __construct(private ResourceInfo $resourceInfo, private ?MainSpanContextInterface $mainSpanContext = null, private ?RequestStack $requestStack = null)
+    public function __construct(private ResourceInfo $resourceInfo, private MainSpanContextInterface|null $mainSpanContext = null, private RequestStack|null $requestStack = null)
     {
     }
 
diff --git a/src/Tracing/Propagation/EventSubscriber/MessengerEventSubscriber.php b/src/Tracing/Propagation/EventSubscriber/MessengerEventSubscriber.php
index 1e30ff1..50fdc0b 100644
--- a/src/Tracing/Propagation/EventSubscriber/MessengerEventSubscriber.php
+++ b/src/Tracing/Propagation/EventSubscriber/MessengerEventSubscriber.php
@@ -21,9 +21,9 @@
 class MessengerEventSubscriber implements EventSubscriberInterface
 {
     private LoggerInterface $logger;
-    private ?ScopeInterface $scope = null;
+    private ScopeInterface|null $scope = null;
 
-    public function __construct(?LoggerInterface $logger = null)
+    public function __construct(LoggerInterface|null $logger = null)
     {
         $this->logger = $logger ?? new NullLogger();
     }
diff --git a/src/Tracing/Propagation/EventSubscriber/RequestEventSubscriber.php b/src/Tracing/Propagation/EventSubscriber/RequestEventSubscriber.php
index 0a7c875..7741470 100644
--- a/src/Tracing/Propagation/EventSubscriber/RequestEventSubscriber.php
+++ b/src/Tracing/Propagation/EventSubscriber/RequestEventSubscriber.php
@@ -26,7 +26,7 @@ public static function getSubscribedEvents(): array
         ];
     }
 
-    public function __construct(private ForcableIdGenerator $forcableIdGenerator, private ?IncomingTraceHeaderResolverInterface $incomingTraceResolver = null)
+    public function __construct(private ForcableIdGenerator $forcableIdGenerator, private IncomingTraceHeaderResolverInterface|null $incomingTraceResolver = null)
     {
     }
 
diff --git a/src/Tracing/Propagation/ForcableIdGenerator.php b/src/Tracing/Propagation/ForcableIdGenerator.php
index 97c7d3a..0c9a24e 100644
--- a/src/Tracing/Propagation/ForcableIdGenerator.php
+++ b/src/Tracing/Propagation/ForcableIdGenerator.php
@@ -14,8 +14,8 @@
 
 final class ForcableIdGenerator implements IdGeneratorInterface, ResetInterface
 {
-    private ?string $traceId = null;
-    private ?string $spanId = null;
+    private string|null $traceId = null;
+    private string|null $spanId = null;
 
     public function __construct(private IdGeneratorInterface $decorated)
     {
diff --git a/src/Tracing/Propagation/IncomingTraceHeaderResolverInterface.php b/src/Tracing/Propagation/IncomingTraceHeaderResolverInterface.php
index 7c8c2d7..626b0c2 100644
--- a/src/Tracing/Propagation/IncomingTraceHeaderResolverInterface.php
+++ b/src/Tracing/Propagation/IncomingTraceHeaderResolverInterface.php
@@ -13,9 +13,9 @@
 
 interface IncomingTraceHeaderResolverInterface
 {
-    public function getTraceId(Request $request): ?string;
+    public function getTraceId(Request $request): string|null;
 
-    public function getSpanId(Request $request): ?string;
+    public function getSpanId(Request $request): string|null;
 
-    public function isSampled(Request $request): ?bool;
+    public function isSampled(Request $request): bool|null;
 }
diff --git a/src/Tracing/Propagation/Messenger/TraceContextStamp.php b/src/Tracing/Propagation/Messenger/TraceContextStamp.php
index dbe08c7..3e96e83 100644
--- a/src/Tracing/Propagation/Messenger/TraceContextStamp.php
+++ b/src/Tracing/Propagation/Messenger/TraceContextStamp.php
@@ -16,7 +16,7 @@
 final class TraceContextStamp implements StampInterface
 {
     private string $traceParent;
-    private ?string $traceState;
+    private string|null $traceState;
 
     public function __construct()
     {
@@ -36,7 +36,7 @@ public function getTraceParent(): string
         return $this->traceParent;
     }
 
-    public function getTraceState(): ?string
+    public function getTraceState(): string|null
     {
         return $this->traceState;
     }
diff --git a/src/Tracing/Propagation/RegexIncomingTraceHeaderResolver.php b/src/Tracing/Propagation/RegexIncomingTraceHeaderResolver.php
index 18d7e16..b298675 100644
--- a/src/Tracing/Propagation/RegexIncomingTraceHeaderResolver.php
+++ b/src/Tracing/Propagation/RegexIncomingTraceHeaderResolver.php
@@ -13,25 +13,25 @@
 
 class RegexIncomingTraceHeaderResolver implements IncomingTraceHeaderResolverInterface
 {
-    public function __construct(private ?string $headerName = null, private ?string $regex = null)
+    public function __construct(private string|null $headerName = null, private string|null $regex = null)
     {
     }
 
-    public function getTraceId(Request $request): ?string
+    public function getTraceId(Request $request): string|null
     {
         $matches = $this->resolve($request);
 
         return $matches['trace'] ?? null;
     }
 
-    public function getSpanId(Request $request): ?string
+    public function getSpanId(Request $request): string|null
     {
         $matches = $this->resolve($request);
 
         return $matches['spanId'] ?? null;
     }
 
-    public function isSampled(Request $request): ?bool
+    public function isSampled(Request $request): bool|null
     {
         $matches = $this->resolve($request);
 
diff --git a/src/Tracing/Sampling/TogglableSampler.php b/src/Tracing/Sampling/TogglableSampler.php
index 4a1cfed..912cff3 100644
--- a/src/Tracing/Sampling/TogglableSampler.php
+++ b/src/Tracing/Sampling/TogglableSampler.php
@@ -20,7 +20,7 @@ final class TogglableSampler implements SamplerInterface, ResetInterface
     /**
      * @var int&SamplingResult::*
      */
-    private ?int $nextDecision = null;
+    private int|null $nextDecision = null;
 
     public function __construct(private SamplerInterface $decorated)
     {
diff --git a/src/Tracing/Serializer/Normalizer/ErrorNormalizer.php b/src/Tracing/Serializer/Normalizer/ErrorNormalizer.php
index 0b5b03e..83a86ce 100644
--- a/src/Tracing/Serializer/Normalizer/ErrorNormalizer.php
+++ b/src/Tracing/Serializer/Normalizer/ErrorNormalizer.php
@@ -18,7 +18,7 @@
 
 class ErrorNormalizer implements NormalizerInterface, SerializerAwareInterface
 {
-    public function __construct(private NormalizerInterface $decorated, private bool $addUrl = false, private ?TraceUrlGeneratorInterface $traceUrlGenerator = null)
+    public function __construct(private NormalizerInterface $decorated, private bool $addUrl = false, private TraceUrlGeneratorInterface|null $traceUrlGenerator = null)
     {
     }
 
@@ -32,7 +32,7 @@ public function setSerializer(SerializerInterface $serializer): void
     /**
      * @return array<class-string, bool>
      */
-    public function getSupportedTypes(?string $format): array
+    public function getSupportedTypes(string|null $format): array
     {
         return [
             FlattenException::class => __CLASS__ === self::class,
@@ -44,7 +44,7 @@ public function getSupportedTypes(?string $format): array
      *
      * @return array<mixed>|\ArrayObject<int|string,mixed>
      */
-    public function normalize($exception, ?string $format = null, array $context = []): array|string|int|float|bool|\ArrayObject|null
+    public function normalize($exception, string|null $format = null, array $context = []): array|string|int|float|bool|\ArrayObject|null
     {
         $data = $this->decorated->normalize($exception, $format, $context);
 
@@ -66,7 +66,7 @@ public function normalize($exception, ?string $format = null, array $context = [
     /**
      * @param array<mixed> $context
      */
-    public function supportsNormalization($data, ?string $format = null, array $context = []): bool
+    public function supportsNormalization($data, string|null $format = null, array $context = []): bool
     {
         return $this->decorated->supportsNormalization($data, $format, $context);
     }
diff --git a/src/Tracing/Tracer.php b/src/Tracing/Tracer.php
index 96741b5..eeb7357 100644
--- a/src/Tracing/Tracer.php
+++ b/src/Tracing/Tracer.php
@@ -21,7 +21,7 @@ public function __construct(private BaseTracerInterface $decorated)
     {
     }
 
-    public function trace(string $operation, ?array $attributes = null, ?int $kind = null, ?Context $parentContext = null): SpanInterface
+    public function trace(string $operation, array|null $attributes = null, int|null $kind = null, Context|null $parentContext = null): SpanInterface
     {
         return $this->decorated->spanBuilder($operation)
             ->setAttributes($attributes ?: [])
diff --git a/src/Tracing/TracerInterface.php b/src/Tracing/TracerInterface.php
index a9a4d38..e84340d 100644
--- a/src/Tracing/TracerInterface.php
+++ b/src/Tracing/TracerInterface.php
@@ -21,5 +21,5 @@ interface TracerInterface extends BaseTracerInterface
      * @param array<string,string> $attributes
      * @param SpanKind::KIND_*     $kind
      */
-    public function trace(string $operation, ?array $attributes = null, ?int $kind = null, ?Context $parentContext = null): SpanInterface;
+    public function trace(string $operation, array|null $attributes = null, int|null $kind = null, Context|null $parentContext = null): SpanInterface;
 }
diff --git a/src/Tracing/Tracing.php b/src/Tracing/Tracing.php
index 25b3e3f..6cd3781 100644
--- a/src/Tracing/Tracing.php
+++ b/src/Tracing/Tracing.php
@@ -18,14 +18,14 @@ final class Tracing
 {
     public const NAME = 'io.opentelemetry.contrib.php';
 
-    private static ?TracerProviderInterface $tracerProvider = null;
+    private static TracerProviderInterface|null $tracerProvider = null;
 
     /**
      * @param non-empty-string     $operation
      * @param array<string,string> $attributes
      * @param SpanKind::KIND_*     $kind
      */
-    public static function trace(string $operation, ?array $attributes = null, ?int $kind = null, ?Context $parentContext = null): SpanInterface
+    public static function trace(string $operation, array|null $attributes = null, int|null $kind = null, Context|null $parentContext = null): SpanInterface
     {
         return static::getTracer()->spanBuilder($operation)
             ->setAttributes($attributes ?: [])
diff --git a/src/Tracing/Twig/Extension/TracingExtension.php b/src/Tracing/Twig/Extension/TracingExtension.php
index 8a2b88a..c06e442 100644
--- a/src/Tracing/Twig/Extension/TracingExtension.php
+++ b/src/Tracing/Twig/Extension/TracingExtension.php
@@ -16,7 +16,7 @@
 
 class TracingExtension extends AbstractExtension
 {
-    public function __construct(private ?TraceUrlGeneratorInterface $traceUrlGenerator = null)
+    public function __construct(private TraceUrlGeneratorInterface|null $traceUrlGenerator = null)
     {
     }
 
@@ -33,7 +33,7 @@ public function getTraceId(): string
         return Span::getCurrent()->getContext()->getTraceId();
     }
 
-    public function getTraceUrl(?string $traceId = null): ?string
+    public function getTraceUrl(string|null $traceId = null): string|null
     {
         if ($traceId && $this->traceUrlGenerator) {
             return $this->traceUrlGenerator->getTraceUrl($traceId);