diff --git a/src/Response.php b/src/Response.php
index 36e375fc..d8cf863e 100644
--- a/src/Response.php
+++ b/src/Response.php
@@ -12,7 +12,8 @@ class Response extends EventEmitter implements WritableStreamInterface
     private $writable = true;
     private $conn;
     private $headWritten = false;
-    private $chunkedEncoding = true;
+    // TODO chunked is a HTTP/1.1 feature that needs proper Request parsing before enabling
+    private $chunkedEncoding = false;
 
     public function __construct(ConnectionInterface $conn)
     {
@@ -74,7 +75,7 @@ private function formatHead($status, array $headers)
     {
         $status = (int) $status;
         $text = isset(ResponseCodes::$statusTexts[$status]) ? ResponseCodes::$statusTexts[$status] : '';
-        $data = "HTTP/1.1 $status $text\r\n";
+        $data = "HTTP/1.0 $status $text\r\n";
 
         foreach ($headers as $name => $value) {
             $name = str_replace(array("\r", "\n"), '', $name);
diff --git a/tests/ResponseTest.php b/tests/ResponseTest.php
index 7692fb83..12b2d0c7 100644
--- a/tests/ResponseTest.php
+++ b/tests/ResponseTest.php
@@ -9,7 +9,7 @@ class ResponseTest extends TestCase
     public function testResponseShouldBeChunkedByDefault()
     {
         $expected = '';
-        $expected .= "HTTP/1.1 200 OK\r\n";
+        $expected .= "HTTP/1.0 200 OK\r\n";
         $expected .= "X-Powered-By: React/alpha\r\n";
         $expected .= "Transfer-Encoding: chunked\r\n";
         $expected .= "\r\n";
@@ -27,7 +27,7 @@ public function testResponseShouldBeChunkedByDefault()
     public function testResponseShouldNotBeChunkedWithContentLength()
     {
         $expected = '';
-        $expected .= "HTTP/1.1 200 OK\r\n";
+        $expected .= "HTTP/1.0 200 OK\r\n";
         $expected .= "X-Powered-By: React/alpha\r\n";
         $expected .= "Content-Length: 22\r\n";
         $expected .= "\r\n";
@@ -97,7 +97,7 @@ public function writeContinueShouldSendContinueLineBeforeRealHeaders()
         $conn
             ->expects($this->at(4))
             ->method('write')
-            ->with($this->stringContains("HTTP/1.1 200 OK\r\n"));
+            ->with($this->stringContains("HTTP/1.0 200 OK\r\n"));
 
         $response = new Response($conn);
         $response->writeContinue();
@@ -128,7 +128,7 @@ public function shouldForwardEndDrainAndErrorEvents()
     public function shouldRemoveNewlinesFromHeaders()
     {
         $expected = '';
-        $expected .= "HTTP/1.1 200 OK\r\n";
+        $expected .= "HTTP/1.0 200 OK\r\n";
         $expected .= "X-Powered-By: React/alpha\r\n";
         $expected .= "FooBar: BazQux\r\n";
         $expected .= "Transfer-Encoding: chunked\r\n";
@@ -148,7 +148,7 @@ public function shouldRemoveNewlinesFromHeaders()
     public function missingStatusCodeTextShouldResultInNumberOnlyStatus()
     {
         $expected = '';
-        $expected .= "HTTP/1.1 700 \r\n";
+        $expected .= "HTTP/1.0 700 \r\n";
         $expected .= "X-Powered-By: React/alpha\r\n";
         $expected .= "Transfer-Encoding: chunked\r\n";
         $expected .= "\r\n";
@@ -167,7 +167,7 @@ public function missingStatusCodeTextShouldResultInNumberOnlyStatus()
     public function shouldAllowArrayHeaderValues()
     {
         $expected = '';
-        $expected .= "HTTP/1.1 200 OK\r\n";
+        $expected .= "HTTP/1.0 200 OK\r\n";
         $expected .= "X-Powered-By: React/alpha\r\n";
         $expected .= "Set-Cookie: foo=bar\r\n";
         $expected .= "Set-Cookie: bar=baz\r\n";
@@ -188,7 +188,7 @@ public function shouldAllowArrayHeaderValues()
     public function shouldIgnoreHeadersWithNullValues()
     {
         $expected = '';
-        $expected .= "HTTP/1.1 200 OK\r\n";
+        $expected .= "HTTP/1.0 200 OK\r\n";
         $expected .= "X-Powered-By: React/alpha\r\n";
         $expected .= "Transfer-Encoding: chunked\r\n";
         $expected .= "\r\n";