diff --git a/README.md b/README.md
index 7fe9af6..bc883f2 100644
--- a/README.md
+++ b/README.md
@@ -42,7 +42,8 @@ This project provides a *simple* API for invoking *async* RPCs to remote web ser
     * [getLocation()](#getlocation)
   * [Proxy](#proxy)
     * [Functions](#functions)
-    * [Processing](#processing)
+    * [Promises](#promises)
+    * [Cancellation](#cancellation)
 * [Install](#install)
 * [Tests](#tests)
 * [License](#license)
@@ -209,7 +210,7 @@ $proxy->myMethod($myArg1, $myArg2)->then(function ($response) {
 Please refer to your WSDL or its accompanying documentation for details
 on which functions and arguments are supported.
 
-#### Processing
+#### Promises
 
 Issuing SOAP functions is async (non-blocking), so you can actually send multiple RPC requests in parallel.
 The web service will respond to each request with a return value. The order is not guaranteed.
@@ -227,6 +228,21 @@ $proxy->demo()->then(
 });
 ```
 
+#### Cancellation
+
+The returned Promise is implemented in such a way that it can be cancelled
+when it is still pending.
+Cancelling a pending promise will reject its value with an Exception and
+clean up any underlying resources.
+
+```php
+$promise = $proxy->demo();
+
+$loop->addTimer(2.0, function () use ($promise) {
+    $promise->cancel();
+});
+```
+
 ## Install
 
 The recommended way to install this library is [through Composer](https://getcomposer.org).
diff --git a/composer.json b/composer.json
index 1471ac9..33ea0da 100644
--- a/composer.json
+++ b/composer.json
@@ -15,9 +15,9 @@
     },
     "require": {
         "php": ">=5.3",
-        "clue/buzz-react": "^2.0 || ^1.0",
+        "clue/buzz-react": "^2.0 || ^1.3",
         "react/event-loop": "^1.0 || ^0.5 || ^0.4 || ^0.3",
-        "react/promise": "~1.0|~2.0",
+        "react/promise": "^2.1 || ^1.2",
         "ext-soap": "*"
     },
     "require-dev": {
diff --git a/tests/FunctionalTest.php b/tests/FunctionalTest.php
index 1b0b16f..15ef710 100644
--- a/tests/FunctionalTest.php
+++ b/tests/FunctionalTest.php
@@ -70,6 +70,32 @@ public function testBlzServiceWithInvalidMethod()
         Block\await($promise, $this->loop);
     }
 
+    /**
+     * @expectedException Exception
+     */
+    public function testCancelCreateClientRejects()
+    {
+        $factory = new Factory($this->loop);
+
+        $promise = $factory->createClient('http://www.thomas-bayer.com/axis2/services/BLZService?wsdl');
+        $promise->cancel();
+
+        Block\await($promise, $this->loop);
+    }
+
+    /**
+     * @expectedException Exception
+     */
+    public function testCancelMethodRejects()
+    {
+        $api = new Proxy($this->client);
+
+        $promise = $api->getBank(array('blz' => '12070000'));
+        $promise->cancel();
+
+        Block\await($promise, $this->loop);
+    }
+
     public function testGetLocationForFunctionName()
     {
         $this->assertEquals('http://www.thomas-bayer.com/axis2/services/BLZService', $this->client->getLocation('getBank'));