diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 00f42c16..4963e575 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -3,6 +3,7 @@ repos:
     rev: v1.46.0
     hooks:
       - id: terraform_fmt
+      - id: terraform_validate
       - id: terraform_docs
       - id: terraform_tflint
         args:
diff --git a/README.md b/README.md
index e877d01b..e28da2d6 100644
--- a/README.md
+++ b/README.md
@@ -84,7 +84,7 @@ module "s3_bucket" {
 
 | Name | Version |
 |------|---------|
-| terraform | >= 0.12.6 |
+| terraform | >= 0.12.26 |
 | aws | >= 3.0 |
 
 ## Providers
@@ -101,11 +101,11 @@ No Modules.
 
 | Name |
 |------|
-| [aws_elb_service_account](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/data-sources/elb_service_account) |
-| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/data-sources/iam_policy_document) |
-| [aws_s3_bucket_policy](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/s3_bucket_policy) |
-| [aws_s3_bucket_public_access_block](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/s3_bucket_public_access_block) |
-| [aws_s3_bucket](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/s3_bucket) |
+| [aws_elb_service_account](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/elb_service_account) |
+| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) |
+| [aws_s3_bucket](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket) |
+| [aws_s3_bucket_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket_policy) |
+| [aws_s3_bucket_public_access_block](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket_public_access_block) |
 
 ## Inputs
 
diff --git a/examples/complete/README.md b/examples/complete/README.md
index d0fb1eb9..9d43a590 100644
--- a/examples/complete/README.md
+++ b/examples/complete/README.md
@@ -29,15 +29,15 @@ Note that this example may create resources which cost money. Run `terraform des
 
 | Name | Version |
 |------|---------|
-| terraform | >= 0.12.6, < 0.14 |
-| aws | >= 3.0, < 4.0 |
+| terraform | >= 0.12.26 |
+| aws | >= 3.0 |
 | random | ~> 2 |
 
 ## Providers
 
 | Name | Version |
 |------|---------|
-| aws | >= 3.0, < 4.0 |
+| aws | >= 3.0 |
 | random | ~> 2 |
 
 ## Modules
@@ -52,11 +52,11 @@ Note that this example may create resources which cost money. Run `terraform des
 
 | Name |
 |------|
-| [aws_canonical_user_id](https://registry.terraform.io/providers/hashicorp/aws/4.0/docs/data-sources/canonical_user_id) |
-| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/4.0/docs/data-sources/iam_policy_document) |
-| [aws_iam_role](https://registry.terraform.io/providers/hashicorp/aws/4.0/docs/resources/iam_role) |
-| [aws_kms_key](https://registry.terraform.io/providers/hashicorp/aws/4.0/docs/resources/kms_key) |
-| [random_pet](https://registry.terraform.io/providers/hashicorp/random/2/docs/resources/pet) |
+| [aws_canonical_user_id](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/canonical_user_id) |
+| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) |
+| [aws_iam_role](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role) |
+| [aws_kms_key](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/kms_key) |
+| [random_pet](https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/pet) |
 
 ## Inputs
 
diff --git a/examples/complete/versions.tf b/examples/complete/versions.tf
index 06cd171a..c0a15fba 100644
--- a/examples/complete/versions.tf
+++ b/examples/complete/versions.tf
@@ -1,8 +1,8 @@
 terraform {
-  required_version = ">= 0.12.6, < 0.14"
+  required_version = ">= 0.12.26"
 
   required_providers {
-    aws    = ">= 3.0, < 4.0"
+    aws    = ">= 3.0"
     random = "~> 2"
   }
 }
diff --git a/examples/notification/README.md b/examples/notification/README.md
index 1dd246f4..44df215a 100644
--- a/examples/notification/README.md
+++ b/examples/notification/README.md
@@ -19,7 +19,7 @@ Note that this example may create resources which cost money. Run `terraform des
 
 | Name | Version |
 |------|---------|
-| terraform | >= 0.12.6 |
+| terraform | >= 0.12.26 |
 | aws | >= 3.0 |
 | null | >= 2 |
 | random | >= 2 |
@@ -47,12 +47,12 @@ Note that this example may create resources which cost money. Run `terraform des
 
 | Name |
 |------|
-| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/data-sources/iam_policy_document) |
-| [aws_sqs_queue_policy](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/sqs_queue_policy) |
-| [aws_sqs_queue](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/sqs_queue) |
-| [null_data_source](https://registry.terraform.io/providers/hashicorp/null/2/docs/data-sources/data_source) |
-| [null_resource](https://registry.terraform.io/providers/hashicorp/null/2/docs/resources/resource) |
-| [random_pet](https://registry.terraform.io/providers/hashicorp/random/2/docs/resources/pet) |
+| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) |
+| [aws_sqs_queue](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sqs_queue) |
+| [aws_sqs_queue_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sqs_queue_policy) |
+| [null_data_source](https://registry.terraform.io/providers/hashicorp/null/latest/docs/data-sources/data_source) |
+| [null_resource](https://registry.terraform.io/providers/hashicorp/null/latest/docs/resources/resource) |
+| [random_pet](https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/pet) |
 
 ## Inputs
 
diff --git a/examples/notification/versions.tf b/examples/notification/versions.tf
index 75422136..2f545e55 100644
--- a/examples/notification/versions.tf
+++ b/examples/notification/versions.tf
@@ -1,5 +1,5 @@
 terraform {
-  required_version = ">= 0.12.6"
+  required_version = ">= 0.12.26"
 
   required_providers {
     aws    = ">= 3.0"
diff --git a/examples/s3-replication/README.md b/examples/s3-replication/README.md
index 72979807..3e4ab191 100644
--- a/examples/s3-replication/README.md
+++ b/examples/s3-replication/README.md
@@ -21,7 +21,7 @@ Note that this example may create resources which cost money. Run `terraform des
 
 | Name | Version |
 |------|---------|
-| terraform | >= 0.12.6 |
+| terraform | >= 0.12.26 |
 | aws | >= 3.0 |
 | random | >= 2.0 |
 
@@ -44,12 +44,12 @@ Note that this example may create resources which cost money. Run `terraform des
 
 | Name |
 |------|
-| [aws_caller_identity](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/data-sources/caller_identity) |
-| [aws_iam_policy_attachment](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/iam_policy_attachment) |
-| [aws_iam_policy](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/iam_policy) |
-| [aws_iam_role](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/iam_role) |
-| [aws_kms_key](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/kms_key) |
-| [random_pet](https://registry.terraform.io/providers/hashicorp/random/2.0/docs/resources/pet) |
+| [aws_caller_identity](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/caller_identity) |
+| [aws_iam_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy) |
+| [aws_iam_policy_attachment](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_policy_attachment) |
+| [aws_iam_role](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/iam_role) |
+| [aws_kms_key](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/kms_key) |
+| [random_pet](https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/pet) |
 
 ## Inputs
 
diff --git a/examples/s3-replication/versions.tf b/examples/s3-replication/versions.tf
index 555675f1..2cd6694d 100644
--- a/examples/s3-replication/versions.tf
+++ b/examples/s3-replication/versions.tf
@@ -1,5 +1,5 @@
 terraform {
-  required_version = ">= 0.12.6"
+  required_version = ">= 0.12.26"
 
   required_providers {
     aws    = ">= 3.0"
diff --git a/modules/notification/README.md b/modules/notification/README.md
index 93a5a2f1..43b1922d 100644
--- a/modules/notification/README.md
+++ b/modules/notification/README.md
@@ -25,12 +25,12 @@ No Modules.
 
 | Name |
 |------|
-| [aws_arn](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/data-sources/arn) |
-| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/data-sources/iam_policy_document) |
-| [aws_lambda_permission](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/lambda_permission) |
-| [aws_s3_bucket_notification](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/s3_bucket_notification) |
-| [aws_sns_topic_policy](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/sns_topic_policy) |
-| [aws_sqs_queue_policy](https://registry.terraform.io/providers/hashicorp/aws/3.0/docs/resources/sqs_queue_policy) |
+| [aws_arn](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/arn) |
+| [aws_iam_policy_document](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/iam_policy_document) |
+| [aws_lambda_permission](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lambda_permission) |
+| [aws_s3_bucket_notification](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/s3_bucket_notification) |
+| [aws_sns_topic_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sns_topic_policy) |
+| [aws_sqs_queue_policy](https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sqs_queue_policy) |
 
 ## Inputs
 
diff --git a/outputs.tf b/outputs.tf
index 27ee7e86..c909f59b 100644
--- a/outputs.tf
+++ b/outputs.tf
@@ -1,39 +1,39 @@
 output "this_s3_bucket_id" {
   description = "The name of the bucket."
-  value       = element(concat(aws_s3_bucket_policy.this.*.id, aws_s3_bucket.this.*.id, list("")), 0)
+  value       = element(concat(aws_s3_bucket_policy.this.*.id, aws_s3_bucket.this.*.id, [""]), 0)
 }
 
 output "this_s3_bucket_arn" {
   description = "The ARN of the bucket. Will be of format arn:aws:s3:::bucketname."
-  value       = element(concat(aws_s3_bucket.this.*.arn, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.arn, [""]), 0)
 }
 
 output "this_s3_bucket_bucket_domain_name" {
   description = "The bucket domain name. Will be of format bucketname.s3.amazonaws.com."
-  value       = element(concat(aws_s3_bucket.this.*.bucket_domain_name, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.bucket_domain_name, [""]), 0)
 }
 
 output "this_s3_bucket_bucket_regional_domain_name" {
   description = "The bucket region-specific domain name. The bucket domain name including the region name, please refer here for format. Note: The AWS CloudFront allows specifying S3 region-specific endpoint when creating S3 origin, it will prevent redirect issues from CloudFront to S3 Origin URL."
-  value       = element(concat(aws_s3_bucket.this.*.bucket_regional_domain_name, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.bucket_regional_domain_name, [""]), 0)
 }
 
 output "this_s3_bucket_hosted_zone_id" {
   description = "The Route 53 Hosted Zone ID for this bucket's region."
-  value       = element(concat(aws_s3_bucket.this.*.hosted_zone_id, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.hosted_zone_id, [""]), 0)
 }
 
 output "this_s3_bucket_region" {
   description = "The AWS region this bucket resides in."
-  value       = element(concat(aws_s3_bucket.this.*.region, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.region, [""]), 0)
 }
 
 output "this_s3_bucket_website_endpoint" {
   description = "The website endpoint, if the bucket is configured with a website. If not, this will be an empty string."
-  value       = element(concat(aws_s3_bucket.this.*.website_endpoint, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.website_endpoint, [""]), 0)
 }
 
 output "this_s3_bucket_website_domain" {
   description = "The domain of the website endpoint, if the bucket is configured with a website. If not, this will be an empty string. This is used to create Route 53 alias records. "
-  value       = element(concat(aws_s3_bucket.this.*.website_domain, list("")), 0)
+  value       = element(concat(aws_s3_bucket.this.*.website_domain, [""]), 0)
 }
diff --git a/versions.tf b/versions.tf
index 9b878f67..84e7b654 100644
--- a/versions.tf
+++ b/versions.tf
@@ -1,5 +1,5 @@
 terraform {
-  required_version = ">= 0.12.6"
+  required_version = ">= 0.12.26"
 
   required_providers {
     aws = ">= 3.0"