diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index d93272e..15e780c 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -2,5 +2,5 @@ Hi! :wave: Thanks for the PR! Here's a quick checklist to make this PR easier to
 ##### PR Checklist
 
 - [ ] Have you run `terraform fmt` on the files in this repo? 
-- [ ] Have you updated the README.md by running `terraform-docs --sort-by-required markdown --header-from HEADER . > README.md`?
+- [ ] Have you updated the README.md by running ` terraform-docs --sort-by-required markdown --header-from HEADER.md . > README.md`?
 ---
\ No newline at end of file
diff --git a/HEADER b/HEADER
deleted file mode 100644
index f0b6c85..0000000
--- a/HEADER
+++ /dev/null
@@ -1,43 +0,0 @@
-/**
- * Overview of high-level configurations steps to set up HA VPN with Amazon Web Services (AWS):
- *
- * ![lifecycle: alpha](https://img.shields.io/badge/lifecycle-alpha-a0c3d2.svg)
- * * Create the HA VPN gateway and a Cloud Router. This creates 2 public IP addresses on the GCP side.
- * * Create two AWS Virtual Private Gateways. This creates 4 public addresses on the AWS side.
- * * Create two AWS Site-to-Site VPN connections and customer gateways, one for each AWS Virtual Private Gateway. Specify a non-overlapping link-local Tunnel IP Range for each tunnel, 4 total. For example, 169.254.1.4/30.
- * * Download the AWS configuration files for the generic device type.
- * * Create four VPN tunnels on the HA VPN gateway.
- * * Configure BGP sessions on the Cloud Router using the BGP IP addresses from the downloaded AWS configuration files.
- *
- *
- * ### Single Region Example
- * ```hcl
- * module "tgw-us-east-1" {
- *    source          = "terraform-aws-modules/transit-gateway/aws"
- *    version         = "1.1.0"
- *    name            = "tgw-example-us-east-1"
- *    description     = "TGW example shared with several other AWS accounts"
- *    amazon_side_asn = "64512"
- *
- *    enable_auto_accept_shared_attachments = true
- *    ram_allow_external_principals         = true
- *
- *    tags = {
- *      Purpose = "tgw example"
- *    }
- *  }
- *
- *  module "cb-us-east-1" {
- *    source                  = "github.com/spotify/terraform-google-aws-hybrid-cloud-vpn"
- *    transit_gateway_id      = module.tgw-us-east-1.this_ec2_transit_gateway_id
- *    google_network          = default
- *    amazon_side_asn         = 64512
- *    google_side_asn         = 65534
- *  }
- * ```
- *
- * ### Refrence Docs
- * https://cloud.google.com/files/CloudVPNGuide-UsingCloudVPNwithAmazonWebServices.pdf
- * https://cloud.google.com/vpn/docs/how-to/creating-ha-vpn
- */
-
diff --git a/HEADER.md b/HEADER.md
new file mode 100644
index 0000000..6b27ce1
--- /dev/null
+++ b/HEADER.md
@@ -0,0 +1,41 @@
+Overview of high-level configurations steps to set up HA VPN with Amazon Web Services (AWS):
+
+![lifecycle: alpha](https://img.shields.io/badge/lifecycle-alpha-a0c3d2.svg)
+* Create the HA VPN gateway and a Cloud Router. This creates 2 public IP addresses on the GCP side.
+* Create two AWS Virtual Private Gateways. This creates 4 public addresses on the AWS side.
+* Create two AWS Site-to-Site VPN connections and customer gateways, one for each AWS Virtual Private Gateway. Specify a non-overlapping link-local Tunnel IP Range for each tunnel, 4 total. For example, 169.254.1.4/30.
+* Download the AWS configuration files for the generic device type.
+* Create four VPN tunnels on the HA VPN gateway.
+* Configure BGP sessions on the Cloud Router using the BGP IP addresses from the downloaded AWS configuration files.
+
+
+### Single Region Example
+```hcl
+module "tgw-us-east-1" { 
+   source          = "terraform-aws-modules/transit-gateway/aws"
+   version         = "1.1.0"
+   name            = "tgw-example-us-east-1"
+   description     = "TGW example shared with several other AWS accounts"
+   amazon_side_asn = "64512"
+
+   enable_auto_accept_shared_attachments = true
+   ram_allow_external_principals         = true
+
+   tags = {
+     Purpose = "tgw example"
+   }
+}
+
+module "cb-us-east-1" {
+   source             = "github.com/spotify/terraform-google-aws-hybrid-cloud-vpn"
+   transit_gateway_id = module.tgw-us-east-1.this_ec2_transit_gateway_id
+   google_network     = default
+   amazon_side_asn    = 64512
+   google_side_asn    = 65534
+}
+```
+ 
+### Refrence Docs
+https://cloud.google.com/files/CloudVPNGuide-UsingCloudVPNwithAmazonWebServices.pdf
+https://cloud.google.com/vpn/docs/how-to/creating-ha-vpn
+
diff --git a/README.md b/README.md
index 480bcad..0c14b1b 100644
--- a/README.md
+++ b/README.md
@@ -23,15 +23,15 @@ module "tgw-us-east-1" {
    tags = {
      Purpose = "tgw example"
    }
- }
+}
 
- module "cb-us-east-1" {
-   source                  = "github.com/spotify/terraform-google-aws-hybrid-cloud-vpn"
-   transit_gateway_id      = module.tgw-us-east-1.this_ec2_transit_gateway_id
-   google_network          = default
-   amazon_side_asn         = 64512
-   google_side_asn         = 65534
- }
+module "cb-us-east-1" {
+   source             = "github.com/spotify/terraform-google-aws-hybrid-cloud-vpn"
+   transit_gateway_id = module.tgw-us-east-1.this_ec2_transit_gateway_id
+   google_network     = default
+   amazon_side_asn    = 64512
+   google_side_asn    = 65534
+}
 ```
 
 ### Refrence Docs  
@@ -42,7 +42,7 @@ https://cloud.google.com/vpn/docs/how-to/creating-ha-vpn
 
 | Name | Version |
 |------|---------|
-| aws | <4.0,>= 2.51.0 |
+| aws | <4.0,>= 3.22.0 |
 | google | <4.0,>= 3.11.0 |
 | google-beta | <4.0,>= 3.11.0 |
 
@@ -50,7 +50,7 @@ https://cloud.google.com/vpn/docs/how-to/creating-ha-vpn
 
 | Name | Version |
 |------|---------|
-| aws | <4.0,>= 2.51.0 |
+| aws | <4.0,>= 3.22.0 |
 | google | <4.0,>= 3.11.0 |
 | google-beta | <4.0,>= 3.11.0 |
 | random | n/a |
@@ -72,4 +72,5 @@ https://cloud.google.com/vpn/docs/how-to/creating-ha-vpn
 |------|-------------|
 | cloud\_router | Map of cloud router attributes. Map should match the exported resources described in the docs https://www.terraform.io/docs/providers/google/r/compute_router.html |
 | ha\_vpn\_gateway\_interfaces | List of objects with interface ID and IP addresses |
+| transit\_gateway\_attachment\_ids | Set of AWS Transit Gateway Attachement IDs |
 
diff --git a/main.tf b/main.tf
index 4900c86..b82dd4c 100644
--- a/main.tf
+++ b/main.tf
@@ -135,7 +135,7 @@ resource "google_compute_router" "router" {
         : var.router_advertise_config.groups
       )
     )
-    dynamic advertised_ip_ranges {
+    dynamic "advertised_ip_ranges" {
       for_each = (
         var.router_advertise_config == null ? {} : (
           var.router_advertise_config.mode != "CUSTOM"
@@ -158,7 +158,7 @@ resource "google_compute_external_vpn_gateway" "external_gateway" {
   redundancy_type = "FOUR_IPS_REDUNDANCY"
   description     = "AWS Transit GW: ${var.transit_gateway_id} in AWS region ${data.aws_region.current.name}"
 
-  dynamic interface {
+  dynamic "interface" {
     for_each = local.external_vpn_gateway_interfaces
     content {
       id         = interface.key
diff --git a/outputs.tf b/outputs.tf
index 1088e42..14be3d8 100644
--- a/outputs.tf
+++ b/outputs.tf
@@ -20,4 +20,12 @@ output "ha_vpn_gateway_interfaces" {
 output "cloud_router" {
   value       = google_compute_router.router
   description = "Map of cloud router attributes. Map should match the exported resources described in the docs https://www.terraform.io/docs/providers/google/r/compute_router.html"
+}
+
+output "transit_gateway_attachment_ids" {
+  description = "Set of AWS Transit Gateway Attachement IDs"
+  value = toset([
+    aws_vpn_connection.vpn-alpha.transit_gateway_attachment_id,
+    aws_vpn_connection.vpn-beta.transit_gateway_attachment_id
+  ])
 }
\ No newline at end of file
diff --git a/versions.tf b/versions.tf
index daf9b24..9543d1e 100644
--- a/versions.tf
+++ b/versions.tf
@@ -16,6 +16,6 @@ terraform {
   required_providers {
     google      = "<4.0,>= 3.11.0"
     google-beta = "<4.0,>= 3.11.0"
-    aws         = "<4.0,>= 2.51.0"
+    aws         = "<4.0,>= 3.22.0"
   }
 }