diff --git a/UPGRADE-5.0.md b/UPGRADE-5.0.md
index 48260cc56fec..abf374dfa04d 100644
--- a/UPGRADE-5.0.md
+++ b/UPGRADE-5.0.md
@@ -480,7 +480,7 @@ Serializer
 Stopwatch
 ---------
 
- * Removed support of passing `null` as 1st (`$id`) argument of `Section::get()` method, pass a valid child section identifier instead.
+ * Removed support for passing `null` as 1st (`$id`) argument of `Section::get()` method, pass a valid child section identifier instead.
 
 Translation
 -----------
diff --git a/src/Symfony/Component/Stopwatch/CHANGELOG.md b/src/Symfony/Component/Stopwatch/CHANGELOG.md
index 85a62f018119..14b7dc6dd5ef 100644
--- a/src/Symfony/Component/Stopwatch/CHANGELOG.md
+++ b/src/Symfony/Component/Stopwatch/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+5.0.0
+-----
+
+ * Removed support for passing `null` as 1st (`$id`) argument of `Section::get()` method, pass a valid child section identifier instead.
+
 4.4.0
 -----
 
diff --git a/src/Symfony/Component/Stopwatch/Stopwatch.php b/src/Symfony/Component/Stopwatch/Stopwatch.php
index 19e59bec501f..9a3fe56d86e7 100644
--- a/src/Symfony/Component/Stopwatch/Stopwatch.php
+++ b/src/Symfony/Component/Stopwatch/Stopwatch.php
@@ -81,7 +81,7 @@ public function openSection(string $id = null)
      *
      * @throws \LogicException When there's no started section to be stopped
      */
-    public function stopSection(?string $id)
+    public function stopSection(string $id)
     {
         $this->stop('__section__');