diff --git a/app/celery/tasks.py b/app/celery/tasks.py
index 48e419781..d83bf7cc2 100644
--- a/app/celery/tasks.py
+++ b/app/celery/tasks.py
@@ -3,7 +3,7 @@ from collections import defaultdict, namedtuple
 from datetime import datetime
 
 from flask import current_app
-from notifications_utils.columns import Columns
+from notifications_utils.insensitive_dict import InsensitiveDict
 from notifications_utils.postal_address import PostalAddress
 from notifications_utils.recipients import RecipientCSV
 from notifications_utils.timezones import convert_utc_to_bst
@@ -351,7 +351,7 @@ def save_letter(
     notification = encryption.decrypt(encrypted_notification)
 
     postal_address = PostalAddress.from_personalisation(
-        Columns(notification['personalisation'])
+        InsensitiveDict(notification['personalisation'])
     )
 
     service = SerialisedService.from_id(service_id)
diff --git a/app/models.py b/app/models.py
index 2486a4045..c6269e421 100644
--- a/app/models.py
+++ b/app/models.py
@@ -3,8 +3,11 @@ import itertools
 import uuid
 
 from flask import current_app, url_for
-from notifications_utils.columns import Columns
+from notifications_utils.insensitive_dict import InsensitiveDict
 from notifications_utils.letter_timings import get_letter_timings
+from notifications_utils.postal_address import (
+    address_lines_1_to_6_and_postcode_keys,
+)
 from notifications_utils.recipients import (
     InvalidEmailError,
     InvalidPhoneError,
@@ -1692,14 +1695,20 @@ class Notification(db.Model):
         }
 
         if self.notification_type == LETTER_TYPE:
-            col = Columns(self.personalisation)
-            serialized['line_1'] = col.get('address_line_1')
-            serialized['line_2'] = col.get('address_line_2')
-            serialized['line_3'] = col.get('address_line_3')
-            serialized['line_4'] = col.get('address_line_4')
-            serialized['line_5'] = col.get('address_line_5')
-            serialized['line_6'] = col.get('address_line_6')
-            serialized['postcode'] = col.get('postcode')
+            personalisation = InsensitiveDict(self.personalisation)
+
+            (
+                serialized['line_1'],
+                serialized['line_2'],
+                serialized['line_3'],
+                serialized['line_4'],
+                serialized['line_5'],
+                serialized['line_6'],
+                serialized['postcode'],
+            ) = (
+                personalisation.get(line) for line in address_lines_1_to_6_and_postcode_keys
+            )
+
             serialized['estimated_delivery'] = \
                 get_letter_timings(serialized['created_at'], postage=self.postage)\
                 .earliest_delivery\
diff --git a/requirements.in b/requirements.in
index 6868d299d..9cba7ec2d 100644
--- a/requirements.in
+++ b/requirements.in
@@ -31,7 +31,7 @@ notifications-python-client==6.0.2
 # PaaS
 awscli-cwlogs==1.4.6
 
-notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@51.3.0
+notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@53.0.0
 
 # gds-metrics requires prometheseus 0.2.0, override that requirement as 0.7.1 brings significant performance gains
 prometheus-client==0.10.1
diff --git a/requirements.txt b/requirements.txt
index a90098a04..0b21f21ea 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -148,7 +148,7 @@ mistune==0.8.4
     # via notifications-utils
 notifications-python-client==6.0.2
     # via -r requirements.in
-notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@51.3.0
+notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@53.0.0
     # via -r requirements.in
 orderedset==2.0.3
     # via notifications-utils
diff --git a/tests/app/celery/test_tasks.py b/tests/app/celery/test_tasks.py
index deb82afc1..08bba3c38 100644
--- a/tests/app/celery/test_tasks.py
+++ b/tests/app/celery/test_tasks.py
@@ -7,7 +7,7 @@ import pytest
 import requests_mock
 from celery.exceptions import Retry
 from freezegun import freeze_time
-from notifications_utils.columns import Row
+from notifications_utils.recipients import Row
 from notifications_utils.template import (
     LetterPrintTemplate,
     PlainTextEmailTemplate,