diff --git a/requirements.in b/requirements.in
index 732458d6d..41a712699 100644
--- a/requirements.in
+++ b/requirements.in
@@ -36,7 +36,7 @@ notifications-python-client==6.0.2
 # PaaS
 awscli-cwlogs==1.4.6
 
-notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@51.0.0
+notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@51.2.1
 
 # 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 0ffd5fe4b..fee9883de 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -153,7 +153,7 @@ 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@51.0.0
+notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@51.2.1
     # via -r requirements.in
 orderedset==2.0.3
     # via notifications-utils