diff --git a/examples/full-cluster-tf-upgrade/common-services/cert.tf b/examples/full-cluster-tf-upgrade/common-services/cert.tf
index af38a09..baa0d8f 100644
--- a/examples/full-cluster-tf-upgrade/common-services/cert.tf
+++ b/examples/full-cluster-tf-upgrade/common-services/cert.tf
@@ -58,7 +58,7 @@ EOM
 
 
 module "cert" {
-  source = "git@github.e.it.census.gov:terraform-modules/aws-tls-certificate"
+  source = "git@github.e.it.census.gov:terraform-modules/aws-tls-certificate?ref=tf-upgrade"
 
   certificate_cn                = local.ca_dns_name
   certificate_san               = [local.ca_dns_name]