Upgrade fails

[dwschulze]

When I run terraform init -upgrade followed by terraform plan I get errors. Why can't this code be upgraded?

var.db_password
  RDS root user password

  Enter a value: 

╷
│ Warning: Argument is deprecated
│ 
│   with module.vpc.aws_eip.nat,
│   on .terraform/modules/vpc/main.tf line 970, in resource "aws_eip" "nat":
│  970:   vpc = true
│ 
│ use domain attribute instead
╵
╷
│ Error: Unsupported argument
│ 
│   on .terraform/modules/vpc/main.tf line 36, in resource "aws_vpc" "this":
│   36:   enable_classiclink               = var.enable_classiclink
│ 
│ An argument named "enable_classiclink" is not expected here.
╵
╷
│ Error: Unsupported argument
│ 
│   on .terraform/modules/vpc/main.tf line 37, in resource "aws_vpc" "this":
│   37:   enable_classiclink_dns_support   = var.enable_classiclink_dns_support
│ 
│ An argument named "enable_classiclink_dns_support" is not expected here.
╵
╷
│ Error: Unsupported argument
│ 
│   on .terraform/modules/vpc/main.tf line 1194, in resource "aws_default_vpc" "this":
│ 1194:   enable_classiclink   = var.default_vpc_enable_classiclink
│ 
│ An argument named "enable_classiclink" is not expected here.
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