diff --git a/UPGRADE-4.3.md b/UPGRADE-4.3.md
index d6a7f00203..4eb383d467 100644
--- a/UPGRADE-4.3.md
+++ b/UPGRADE-4.3.md
@@ -1,6 +1,13 @@
 UPGRADE FROM 4.2 to 4.3
 =======================
 
+BrowserKit
+----------
+
+ * Marked `Response` final.
+ * Deprecated `Response::buildHeader()`
+ * Deprecated `Response::getStatus()`, use `Response::getStatusCode()` instead
+
 Config
 ------
 
diff --git a/UPGRADE-5.0.md b/UPGRADE-5.0.md
index cf677c478a..f446a7c15a 100644
--- a/UPGRADE-5.0.md
+++ b/UPGRADE-5.0.md
@@ -4,6 +4,9 @@ UPGRADE FROM 4.x to 5.0
 BrowserKit
 ----------
 
+ * Removed the possibility to extend `Response` by making it final.
+ * Removed `Response::buildHeader()`
+ * Removed `Response::getStatus()`, use `Response::getStatusCode()` instead
  * The `Client::submit()` method has a new `$serverParameters` argument.
 
 Cache
diff --git a/src/Symfony/Component/BrowserKit/CHANGELOG.md b/src/Symfony/Component/BrowserKit/CHANGELOG.md
index 51d8fbf48c..5ff92bb024 100644
--- a/src/Symfony/Component/BrowserKit/CHANGELOG.md
+++ b/src/Symfony/Component/BrowserKit/CHANGELOG.md
@@ -1,6 +1,13 @@
 CHANGELOG
 =========
 
+4.3.0
+-----
+
+ * Marked `Response` final.
+ * Deprecated `Response::buildHeader()`
+ * Deprecated `Response::getStatus()`, use `Response::getStatusCode()` instead
+
 4.2.0
 -----
 
diff --git a/src/Symfony/Component/BrowserKit/Client.php b/src/Symfony/Component/BrowserKit/Client.php
index d483dbcb07..0d1382a5f0 100644
--- a/src/Symfony/Component/BrowserKit/Client.php
+++ b/src/Symfony/Component/BrowserKit/Client.php
@@ -409,7 +409,7 @@ abstract class Client
 
         $this->cookieJar->updateFromResponse($this->internalResponse, $uri);
 
-        $status = $this->internalResponse->getStatus();
+        $status = $this->internalResponse->getStatusCode();
 
         if ($status >= 300 && $status < 400) {
             $this->redirect = $this->internalResponse->getHeader('Location');
@@ -599,7 +599,7 @@ abstract class Client
 
         $request = $this->internalRequest;
 
-        if (\in_array($this->internalResponse->getStatus(), array(301, 302, 303))) {
+        if (\in_array($this->internalResponse->getStatusCode(), array(301, 302, 303))) {
             $method = 'GET';
             $files = array();
             $content = null;
diff --git a/src/Symfony/Component/BrowserKit/Response.php b/src/Symfony/Component/BrowserKit/Response.php
index 6c50aeee43..845be10b68 100644
--- a/src/Symfony/Component/BrowserKit/Response.php
+++ b/src/Symfony/Component/BrowserKit/Response.php
@@ -13,11 +13,16 @@ namespace Symfony\Component\BrowserKit;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @final since Symfony 4.3
  */
 class Response
 {
+    /** @internal */
     protected $content;
+    /** @internal */
     protected $status;
+    /** @internal */
     protected $headers;
 
     /**
@@ -45,10 +50,10 @@ class Response
         $headers = '';
         foreach ($this->headers as $name => $value) {
             if (\is_string($value)) {
-                $headers .= $this->buildHeader($name, $value);
+                $headers .= sprintf("%s: %s\n", $name, $value);
             } else {
                 foreach ($value as $headerValue) {
-                    $headers .= $this->buildHeader($name, $headerValue);
+                    $headers .= sprintf("%s: %s\n", $name, $headerValue);
                 }
             }
         }
@@ -63,9 +68,13 @@ class Response
      * @param string $value The header value
      *
      * @return string The built header line
+     *
+     * @deprecated since Symfony 4.3
      */
     protected function buildHeader($name, $value)
     {
+        @trigger_error(sprintf('The "%s()" method is deprecated since Symfony 4.3.', __METHOD__), E_USER_DEPRECATED);
+
         return sprintf("%s: %s\n", $name, $value);
     }
 
@@ -83,8 +92,17 @@ class Response
      * Gets the response status code.
      *
      * @return int The response status code
+     *
+     * @deprecated since Symfony 4.3, use getStatusCode() instead
      */
     public function getStatus()
+    {
+        @trigger_error(sprintf('The "%s()" method is deprecated since Symfony 4.3, use getStatusCode() instead.', __METHOD__), E_USER_DEPRECATED);
+
+        return $this->status;
+    }
+
+    public function getStatusCode(): int
     {
         return $this->status;
     }
diff --git a/src/Symfony/Component/BrowserKit/Tests/ClientTest.php b/src/Symfony/Component/BrowserKit/Tests/ClientTest.php
index 1a34c623bc..e4cec8b393 100644
--- a/src/Symfony/Component/BrowserKit/Tests/ClientTest.php
+++ b/src/Symfony/Component/BrowserKit/Tests/ClientTest.php
@@ -52,7 +52,7 @@ class TestClient extends Client
     protected function filterResponse($response)
     {
         if ($response instanceof SpecialResponse) {
-            return new Response($response->getContent(), $response->getStatus(), $response->getHeaders());
+            return new Response($response->getContent(), $response->getStatusCode(), $response->getHeaders());
         }
 
         return $response;
diff --git a/src/Symfony/Component/BrowserKit/Tests/ResponseTest.php b/src/Symfony/Component/BrowserKit/Tests/ResponseTest.php
index 0ba4e3b3a7..8afebe454c 100644
--- a/src/Symfony/Component/BrowserKit/Tests/ResponseTest.php
+++ b/src/Symfony/Component/BrowserKit/Tests/ResponseTest.php
@@ -22,12 +22,21 @@ class ResponseTest extends TestCase
         $this->assertEquals('foo', $response->getContent(), '->getContent() returns the content of the response');
     }
 
+    /**
+     * @group legacy
+     */
     public function testGetStatus()
     {
         $response = new Response('foo', 304);
         $this->assertEquals('304', $response->getStatus(), '->getStatus() returns the status of the response');
     }
 
+    public function testGetStatusCode()
+    {
+        $response = new Response('foo', 304);
+        $this->assertEquals('304', $response->getStatusCode(), '->getStatusCode() returns the status of the response');
+    }
+
     public function testGetHeaders()
     {
         $response = new Response('foo', 200, array('foo' => 'bar'));