diff --git a/examples/full-setup-tf-upgrade/subdirectory.versions.tf.off b/examples/full-setup-tf-upgrade/subdirectory.versions.tf.off
new file mode 100644
index 0000000..5d897c3
--- /dev/null
+++ b/examples/full-setup-tf-upgrade/subdirectory.versions.tf.off
@@ -0,0 +1,15 @@
+# if the VPC directory has been converted to TF 1.x (you'll note a file vpc/REGION/vpcN/versin.tf which says required version > 1.0
+# you will need to enable the variable valition experiment in TF 0.12.  If your current directory is 0.13 or greater, do
+# NOT include this file, as the exeriment start in 0.12.20 and ended in 0.13.0.  See:
+#
+# * https://github.com/hashicorp/terraform/blob/v0.12/CHANGELOG.md
+# * https://github.com/hashicorp/terraform/blob/v0.13/CHANGELOG.md
+#
+# add this file to $(git root)/includes.d/subdirectory.versions.tf
+# link it with this statemtn in tf-run.data
+#   LINKTOP includes.d/subdirectory.versions.tf
+
+# only >= 0.12.20  and < 0.13
+terraform {
+  experiments = [variable_validation]
+}
diff --git a/examples/full-setup-tf-upgrade/variables.vpc.tf b/examples/full-setup-tf-upgrade/variables.vpc.tf
index 8c8b6e1..c95b777 100644
--- a/examples/full-setup-tf-upgrade/variables.vpc.tf
+++ b/examples/full-setup-tf-upgrade/variables.vpc.tf
@@ -107,7 +107,7 @@ variable "tgw_environment" {
 
   validation {
     condition     = var.tgw_environment == null || contains(["services", "dev", "test", "stage", "prod", "cre"], var.tgw_environment)
-    error_message = "The tgw_environment must contain one of the legal values: services, dev, test, stage, prod, cre"
+    error_message = "The tgw_environment must contain one of the legal values: services, dev, test, stage, prod, cre."
   }
 }