diff --git a/src/DataCollector/DataCollectorSymfonyCompatibilityTrait.php b/src/DataCollector/DataCollectorSymfonyCompatibilityTrait.php
index 33f3006..e0acae6 100644
--- a/src/DataCollector/DataCollectorSymfonyCompatibilityTrait.php
+++ b/src/DataCollector/DataCollectorSymfonyCompatibilityTrait.php
@@ -16,7 +16,7 @@ abstract protected function doCollect(Request $request, Response $response, \Thr
      *
      * @return void
      */
-    public function collect(Request $request, Response $response, \Throwable $exception = null)
+    public function collect(Request $request, Response $response, \Throwable $exception = null): void
     {
         $this->doCollect($request, $response, $exception);
     }
diff --git a/src/EightPointsGuzzleBundle.php b/src/EightPointsGuzzleBundle.php
index 5787c18..2fc605c 100644
--- a/src/EightPointsGuzzleBundle.php
+++ b/src/EightPointsGuzzleBundle.php
@@ -60,7 +60,7 @@ public function getContainerExtension() : ExtensionInterface
      *
      * @return void
      */
-    public function boot()
+    public function boot(): void
     {
         foreach ($this->plugins as $plugin) {
             $plugin->boot();