diff --git a/requirements.txt b/requirements.txt
index 73cf5b94b..98b9ef1da 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -29,6 +29,6 @@ notifications-python-client>=3.1,<3.2
 awscli>=1.11,<1.12
 awscli-cwlogs>=1.4,<1.5
 
-git+https://github.com/alphagov/notifications-utils.git@13.9.6#egg=notifications-utils==13.9.6
+git+https://github.com/alphagov/notifications-utils.git@15.0.0#egg=notifications-utils==15.0.0
 
 git+https://github.com/alphagov/boto.git@2.43.0-patch3#egg=boto==2.43.0-patch3
diff --git a/tests/app/celery/test_tasks.py b/tests/app/celery/test_tasks.py
index 671d52189..7a410bc60 100644
--- a/tests/app/celery/test_tasks.py
+++ b/tests/app/celery/test_tasks.py
@@ -1018,4 +1018,4 @@ def test_dvla_letter_template(sample_letter_notification):
     letter = LetterDVLATemplate(t,
                                 sample_letter_notification.personalisation,
                                 12345)
-    assert str(letter) == "140|500|001||201703230012345|23032017||||||||||||A1|A2|A3|A4|A5|A6||A_POST||||||||Template subject|Dear Sir/Madam, Hello. Yours Truly, The Government.<cr><cr>"  # noqa
+    assert str(letter) == "140|500|001||201703230012345|||||||||||||A1|A2|A3|A4|A5|A6||A_POST|||||||||23 March 2017<cr><cr><h1>Template subject<normal><cr><cr>Dear Sir/Madam, Hello. Yours Truly, The Government.<cr><cr>"  # noqa
diff --git a/tests/app/notifications/rest/test_send_notification.py b/tests/app/notifications/rest/test_send_notification.py
index 90e2c64e7..d6a4e9c31 100644
--- a/tests/app/notifications/rest/test_send_notification.py
+++ b/tests/app/notifications/rest/test_send_notification.py
@@ -133,6 +133,65 @@ def test_send_notification_with_placeholders_replaced(notify_api, sample_email_t
             assert response_data['subject'] == 'Jo'
 
 
+@pytest.mark.parametrize('personalisation, expected_body, expected_subject', [
+    (
+        ['Jo', 'John', 'Josephine'],
+        (
+            'Hello \n\n'
+            '* Jo\n'
+            '* John\n'
+            '* Josephine\n'
+            'This is an email from GOV.\u200BUK'
+        ),
+        'Jo, John and Josephine',
+    ),
+    (
+        6,
+        (
+            'Hello 6\n'
+            'This is an email from GOV.\u200BUK'
+        ),
+        '6',
+    ),
+    pytest.mark.xfail((
+        None,
+        ('we consider None equivalent to missing personalisation'),
+        '',
+    )),
+])
+def test_send_notification_with_placeholders_replaced_with_unusual_types(
+    client,
+    sample_email_template_with_placeholders,
+    mocker,
+    personalisation,
+    expected_body,
+    expected_subject,
+):
+    mocked = mocker.patch('app.celery.provider_tasks.deliver_email.apply_async')
+
+    response = client.post(
+        path='/notifications/email',
+        data=json.dumps(
+            {
+                'to': 'ok@ok.com',
+                'template': str(sample_email_template_with_placeholders.id),
+                'personalisation': {
+                    'name': personalisation
+                }
+            }
+        ),
+        headers=[
+            ('Content-Type', 'application/json'),
+            create_authorization_header(service_id=sample_email_template_with_placeholders.service.id)
+        ]
+    )
+
+    assert response.status_code == 201
+    response_data = json.loads(response.data)['data']
+    assert response_data['body'] == expected_body
+    assert response_data['subject'] == expected_subject
+
+
 def test_should_not_send_notification_for_archived_template(notify_api, sample_template):
     with notify_api.test_request_context():
         with notify_api.test_client() as client: