diff --git a/CHANGELOG.md b/CHANGELOG.md
index e0dafca05341f635569e4563508ed66e2333aeb5..0a72b143bfe2e72ae14a0c2e190cf9296d193d5d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
+## [1.2.1] - 2020-12-08
+### Fixed
+- default headers should overwrite build in headers
+
 ## [1.2.0] - 2019-06-12
 ### Fixed
 - CacheResolver in cached client
+
 ## [1.1.0] - 2019-05-30
 ### Added
 - Timeout in api client options interface
diff --git a/src/Client/ClientImplementation.php b/src/Client/ClientImplementation.php
index 3777c5a1fdfe6dd0a9d7a51073944fa5159c9003..b2bac6ca774649ec070b0988b7eb531414b7aaf6 100644
--- a/src/Client/ClientImplementation.php
+++ b/src/Client/ClientImplementation.php
@@ -151,7 +151,7 @@ class ClientImplementation implements Client, LoggerAwareInterface
             'Accept-Encoding' => '*',
             'Content-Type' => $this->serializer->getMime()
         );
-        $headers = array_merge($this->defaultRequestHeaders, $headers);
+        $headers = array_merge($headers, $this->defaultRequestHeaders);
         return array_merge($headers, $request->getHeaders());
     }