diff --git a/CHANGELOG.md b/CHANGELOG.md
index a45fcba..3c90ecb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Change Log
 
-## 2.0 (unreleased)
+## 2.0.0 - 2019-02-03
 
 ### Changed
 - HttpClientRouter now throws a HttpClientNoMatchException instead of a RequestException if it can not find a client for the request.
@@ -10,7 +10,7 @@
 - Abstract method `HttpClientPool::chooseHttpClient()` has now an explicit return type (`Http\Client\Common\HttpClientPoolItem`)
 - Interface method `Plugin::handleRequest(...)` has now an explicit return type (`Http\Promise\Promise`)
 - Made  classes final that are not intended to be extended.
-  Added interfaces for BatchClient, HttpClientRouter and HttpMethodsClient.
+- Added interfaces for BatchClient, HttpClientRouter and HttpMethodsClient.
   (These interfaces use the `Interface` suffix to avoid name collisions.)
 - Added an interface for HttpClientPool and moved the abstract class to the HttpClientPool sub namespace.
 - AddPathPlugin: Do not add the prefix if the URL already has the same prefix.
diff --git a/src/BatchClientInterface.php b/src/BatchClientInterface.php
index 4fc70e8..d42eb2d 100644
--- a/src/BatchClientInterface.php
+++ b/src/BatchClientInterface.php
@@ -22,7 +22,7 @@ interface BatchClientInterface
      * You may not assume that the requests are executed in a particular order. If the order matters
      * for your application, use sendRequest sequentially.
      *
-     * @param RequestInterface[] The requests to send
+     * @param RequestInterface[] $requests The requests to send
      *
      * @return BatchResult Containing one result per request
      *
diff --git a/src/Exception/BatchException.php b/src/Exception/BatchException.php
index 46d1e47..cbda665 100644
--- a/src/Exception/BatchException.php
+++ b/src/Exception/BatchException.php
@@ -24,6 +24,7 @@ final class BatchException extends TransferException
     public function __construct(BatchResult $result)
     {
         $this->result = $result;
+        parent::__construct();
     }
 
     /**
diff --git a/src/Plugin/ContentTypePlugin.php b/src/Plugin/ContentTypePlugin.php
index f3944dd..c3fb25c 100644
--- a/src/Plugin/ContentTypePlugin.php
+++ b/src/Plugin/ContentTypePlugin.php
@@ -106,9 +106,6 @@ private function isJson(StreamInterface $stream): bool
         return JSON_ERROR_NONE === json_last_error();
     }
 
-    /**
-     * @param $stream StreamInterface
-     */
     private function isXml(StreamInterface $stream): bool
     {
         if (!function_exists('simplexml_load_string')) {
diff --git a/src/PluginClient.php b/src/PluginClient.php
index 8288445..7a44aab 100644
--- a/src/PluginClient.php
+++ b/src/PluginClient.php
@@ -25,7 +25,7 @@ final class PluginClient implements HttpClient, HttpAsyncClient
     /**
      * An HTTP async client.
      *
-     * @var HttpAsyncClient
+     * @var HttpAsyncClient|HttpClient
      */
     private $client;
 
diff --git a/src/PluginClientFactory.php b/src/PluginClientFactory.php
index 6ae5091..3806e09 100644
--- a/src/PluginClientFactory.php
+++ b/src/PluginClientFactory.php
@@ -16,7 +16,7 @@
 final class PluginClientFactory
 {
     /**
-     * @var callable
+     * @var callable|null
      */
     private static $factory;