diff --git a/src/TaskManager.php b/src/TaskManager.php
index b30c397..a8a92a7 100644
--- a/src/TaskManager.php
+++ b/src/TaskManager.php
@@ -260,9 +260,9 @@ class TaskManager
             'project'     => $task->getProject(),
             'priority'    => $task->getPriority(),
             'tags'        => $task->getTags(),
-            'due'         => $task->getDue() ? $task->getDue()->format('Ymd\THis\Z') : null,
-            'wait'        => $task->getWait() ? $task->getWait()->format('Ymd\THis\Z') : null,
-            'until'       => $task->getUntil() ? $task->getUntil()->format('Ymd\THis\Z') : null
+            'due'         => $this->transformDate($task->getDue()),
+            'wait'        => $this->transformDate($task->getWait()),
+            'until'       => $this->transformDate($task->getUntil())
         ];
 
         if ($task->getRecurring()) {
@@ -326,6 +326,22 @@ class TaskManager
         $refProp->setValue($task, $value);
     }
 
+    /**
+     * @param \DateTime $dateTime
+     * @return null|string
+     */
+    private function transformDate(\DateTime $dateTime = null)
+    {
+        if (!$dateTime) {
+            return null;
+        }
+
+        $dateTime = clone $dateTime;
+        $dateTime->setTimezone(new \DateTimeZone('UTC'));
+
+        return $dateTime->format('Ymd\THis\Z');
+    }
+
     /**
      * @return Serializer
      */
diff --git a/tests/TaskManagerTest.php b/tests/TaskManagerTest.php
index 42de606..a95bcb8 100644
--- a/tests/TaskManagerTest.php
+++ b/tests/TaskManagerTest.php
@@ -23,10 +23,20 @@ class TaskManagerTest extends \PHPUnit_Framework_TestCase
      */
     protected $taskManager;
 
+    /**
+     * @var string
+     */
+    protected $taskDir;
+
     public function setUp()
     {
-        $this->tearDown();
-        $this->taskwarrior = new Taskwarrior(__DIR__ . '/.taskrc', __DIR__ . '/.task');
+        $this->taskDir = __DIR__;
+
+        $fs = new Filesystem();
+        $fs->remove($this->taskDir . '/.taskrc');
+        $fs->remove($this->taskDir . '/.task');
+
+        $this->taskwarrior = new Taskwarrior($this->taskDir . '/.taskrc', $this->taskDir . '/.task');
         $this->taskManager = new TaskManager($this->taskwarrior);
         $this->taskwarrior->version(); // to initialise
     }
@@ -34,8 +44,8 @@ class TaskManagerTest extends \PHPUnit_Framework_TestCase
     public function tearDown()
     {
         $fs = new Filesystem();
-        $fs->remove(__DIR__ . '/.taskrc');
-        $fs->remove(__DIR__ . '/.task');
+        $fs->remove($this->taskDir . '/.taskrc');
+        $fs->remove($this->taskDir . '/.task');
     }
 
     public function testEmpty()
@@ -707,6 +717,6 @@ class TaskManagerTest extends \PHPUnit_Framework_TestCase
      */
     private function createDateTime($string = 'now')
     {
-        return new \DateTime($string);
+        return new \Carbon\Carbon($string);
     }
 }
\ No newline at end of file