diff --git a/README.md b/README.md
index 2f197ae..f4196a1 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,8 @@
 ## Re2o - API client
 
 This project is providing an abstraction layer to easily use the API of Re2o.
+
+## Requirements
+
+* python3
+* python3-iso8601
diff --git a/re2oapi/client.py b/re2oapi/client.py
index 54c28df..13f120d 100644
--- a/re2oapi/client.py
+++ b/re2oapi/client.py
@@ -1,6 +1,7 @@
 import requests
 from requests.exceptions import HTTPError
 import datetime
+import iso8601
 
 from . import endpoints
 from . import exceptions
@@ -32,10 +33,7 @@ class Re2oAPIClient:
         response = response.json()
         return {
             'token': response['token'],
-            'expiration': datetime.datetime.strptime(
-                response['expiration'],
-                '%Y-%m-%dT%H:%M:%S.%fZ'
-            )
+            'expiration': iso8601.parse_date(response['expiration'])
         }
 
     def get_token(self):