read_replicas_mode & replica_count variables are not expected in google_redis_instance

We have used the memory store module for spinning up a redis instance on GCP. However, at a later stage, when we try to enable READ REPLICA via terraform it doesn't accept.

References:

https://github.com/terraform-google-modules/terraform-google-memorystore

module "memorystore_replica" {
  source  = "terraform-google-modules/memorystore/google"
  version = "4.0.0"

  redis_version           = "REDIS_6_X"
  name                    = "${module.project.project_name}-redisreadreplica-${module.locations.region_codes[var.region]}-instance"
  project                 = module.project.project_id
  region                  = var.region
  authorized_network      = local.vpc
  connect_mode            = var.redis_connection_type
  memory_size_gb          = var.redis_memory_size_gb
  transit_encryption_mode = "DISABLED"
  labels                  = var.labels
  replica_count           = 2
  read_replicas_mode      = "READ_REPLICAS_ENABLED"
}

resource "google_redis_instance" "default" {
  depends_on = [module.enable_apis]

  project        = var.project
  name           = var.name
  tier           = var.tier
  memory_size_gb = var.memory_size_gb
  connect_mode   = var.connect_mode

  region                  = var.region
  location_id             = var.location_id
  alternative_location_id = var.alternative_location_id

  authorized_network = var.authorized_network

  redis_version     = var.redis_version
  redis_configs     = var.redis_configs
  display_name      = var.display_name
  reserved_ip_range = var.reserved_ip_range

  labels = var.labels

  auth_enabled = var.auth_enabled

  transit_encryption_mode = var.transit_encryption_mode
}

Error: Unsupported argument
│ 
│   on main.tf line 357, in module "memorystore_replica":
│  357:   replica_count           = 2
│ 
│ An argument named "replica_count" is not expected here.
╵
╷
│ Error: Unsupported argument
│ 
│   on main.tf line 358, in module "memorystore_replica":
│  358:   read_replicas_mode      = "READ_REPLICAS_ENABLED"
│ 
│ An argument named "read_replicas_mode" is not expected here

Any help appreciated!