GitLab CI Runners faild InvalidParameterCombination: Cannot find upgrade path from 5.7.38 to 5.6 , Terraform

GitLab CI Runners faild the jbo with the following error message

│ Error: Error modifying DB Instance legacy-dms: InvalidParameterCombination: Cannot find upgrade path from 5.7.38 to 5.6.
│   status code: 400, request id: e7740193-bf98-464c-a1b3-4124d7f5d909
│ 
│   with module.db.module.db_instance.aws_db_instance.this[0],
│   on .terraform/modules/db/modules/db_instance/main.tf line 45, in resource "aws_db_instance" "this":
│   45: resource "aws_db_instance" "this" {
│ 
╵

Terraform hcl File :

inputs = {

  # Identifier is name in AWS and should be unique in the account
  identifier = "test-dms"
  # Name is actual DB name (doesn't need to be unique)
  name = "PNRQ"

  # Set the following carefully on valid RDS values:
  engine         = "mysql"
  engine_version = "5.6"
  # One year old bug, creating option groups when the default should be used
  # So we have to explicitly set it to the default
  # https://github.com/terraform-aws-modules/terraform-aws-rds/issues/272
  # https://github.com/terraform-aws-modules/terraform-aws-rds/issues/188
  option_group_name = "default:mysql-5-6"
  port              = 3306

  # Change these depending on size/load requirements of the DB and environment
  instance_class    = "db.t3.micro"
  allocated_storage = 20
  multi_az          = false

  # Boilerplate for VPC
  vpc_id         = dependency.vpc.outputs.vpc_id
  vpc_subnet_ids = dependency.vpc.outputs.private_subnets
  allowed_security_groups = [
    # Allow EKS connection
    dependency.eks.outputs.worker_security_group_id,
    # Allow infra runner connection
    dependency.infra_ci.outputs.runner_sg_id
  ]
}

We have aws RDS test-dms Engine version 5.7.38

and I have already updated the ACM certificate associated with this account.

Can anyone assist me in resolving this problem? I would greatly appreciate any help provided.