diff --git a/infrastructure/terraform/components/api/module_sqs_letter_updates.tf b/infrastructure/terraform/components/api/module_sqs_letter_updates.tf
index 472afb81..5a00a0fc 100644
--- a/infrastructure/terraform/components/api/module_sqs_letter_updates.tf
+++ b/infrastructure/terraform/components/api/module_sqs_letter_updates.tf
@@ -2,11 +2,14 @@ module "sqs_letter_updates" {
   source = "https://github.com/NHSDigital/nhs-notify-shared-modules/releases/download/v2.0.26/terraform-sqs.zip"
 
   aws_account_id = var.aws_account_id
-  component      = var.component
-  environment    = var.environment
-  project        = var.project
-  region         = var.region
-  name           = "letter-updates"
+  component                   = var.component
+  environment                 = var.environment
+  project                     = var.project
+  region                      = var.region
+  name                        = "letter-updates"
+  fifo_queue                  = true
+  content_based_deduplication = true
+
 
   sqs_kms_key_arn = module.kms.key_arn
 
diff --git a/infrastructure/terraform/modules/eventsub/sns_topic.tf b/infrastructure/terraform/modules/eventsub/sns_topic.tf
index cc30db15..1b7b5b84 100644
--- a/infrastructure/terraform/modules/eventsub/sns_topic.tf
+++ b/infrastructure/terraform/modules/eventsub/sns_topic.tf
@@ -1,6 +1,8 @@
 resource "aws_sns_topic" "main" {
-  name              = local.csi
-  kms_master_key_id = var.kms_key_arn
+  name                        = local.csi
+  kms_master_key_id           = var.kms_key_arn
+  fifo_topic                  = true
+  content_based_deduplication = true
 
   application_failure_feedback_role_arn    = var.enable_sns_delivery_logging == true ? aws_iam_role.sns_delivery_logging_role[0].arn : null
   application_success_feedback_role_arn    = var.enable_sns_delivery_logging == true ? aws_iam_role.sns_delivery_logging_role[0].arn : null