diff --git a/composer.json b/composer.json
index 2768e4bd..ece07477 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
         }
     },
     "require": {
-        "php": ">=5.3.23",
+        "php": ">=5.5",
         "zendframework/zend-server": "~2.5",
         "zendframework/zend-stdlib": "~2.5",
         "zendframework/zend-uri": "~2.5"
diff --git a/test/Client/DotNetTest.php b/test/Client/DotNetTest.php
index ed6cc9e2..153eba98 100644
--- a/test/Client/DotNetTest.php
+++ b/test/Client/DotNetTest.php
@@ -92,10 +92,9 @@ public function testCurlClientRequestIsDoneWhenUsingNtlmAuthentication()
      */
     public function testDefaultSoapClientRequestIsDoneWhenNotUsingNtlmAuthentication()
     {
-        $unitTest = $this;
         $soapClient = new Common(
-            function (Common $client, $request, $location, $action, $version, $oneWay = null) use ($unitTest) {
-                $unitTest->assertEquals('http://unit/test#TestMethod', $action);
+            function (Common $client, $request, $location, $action, $version, $oneWay = null) {
+                $this->assertEquals('http://unit/test#TestMethod', $action);
                 $result = '<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">'
                     . '<s:Body>';