diff --git a/cert_viewer/notifier.py b/cert_viewer/notifier.py
index 605bb77..7778fb3 100644
--- a/cert_viewer/notifier.py
+++ b/cert_viewer/notifier.py
@@ -56,7 +56,7 @@ def notify(self, recipient_email, first_name, last_name):
             logging.debug('sending mandrill receipt template')
             result = mandrill_client.messages.send_template(template_name='receipt-template',
                                                             template_content=template_content, message=message,
-                                                            async=False)
+                                                            send_async=False)
             return result
         except mandrill.Error as e:
             error_message = 'A mandrill error occurred: %s - %s' % (
diff --git a/requirements.txt b/requirements.txt
index 388d1f6..8b412d0 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -5,7 +5,7 @@ configargparse>=0.13.0
 flasgger>=0.8.3
 Flask>=1.0
 Flask-PyMongo>=0.5.1
-Flask-Themes2==0.1.4
+Flask-Themes2>0.1.4
 Flask-WTF>=0.14.2
 mandrill>=1.0.57
 mock>=2.0.0