Having issue getting node_to_node_encryption enabled in elasticsearch node

Hi,

I am trying to deploy an elasticserach node with node_to_node_encryption enabled, but getting following error when I am running terraform plan command.

Error: Unsupported block type
│ 
│   on main.tf line 19, in resource "aws_elasticsearch_domain" "elasticsearch":
│   19:   node_to_node_encryption_options {
│ 
│ Blocks of type "node_to_node_encryption_options" are not expected here.

main.tf

# Configure the AWS provider
provider "aws" {
  region = var.region
}

# Define the Elasticsearch domain
resource "aws_elasticsearch_domain" "elasticsearch" {
  domain_name           = var.name
  elasticsearch_version = var.elasticsearch_version
  cluster_config {
    instance_type        = var.instance_type
    instance_count       = var.instance_count
    dedicated_master_enabled = false
  }
  ebs_options {
    ebs_enabled = true
    volume_size = var.volume_size
  }
  node_to_node_encryption_options {
    enabled = true
  }
  tags = {
    Environment = var.environment
  }
}

variables.tf

variable "name" {

type = string

}

variable "region" {

type = string

}

variable "elasticsearch_version" {

type = string

}

variable "instance_type" {

type = string

}

variable "instance_count" {

type = number

}

variable "volume_size" {

type = number

}

variable "environment" {

type = string

}

terraform.tfvars

name = "my-elasticsearch"

region = "us-west-2"

elasticsearch_version = "7.18"

instance_type = "t2.small.elasticsearch"

instance_count = 1

volume_size = 10

environment = "dev"

Any clue why am I getting the error? thanks