Formulae updates are automated, which means that you can install the latest updates as soon as they’re released.
But:
$ terraform output
Failed to load state: state snapshot was created by Terraform v0.13.5, which is newer than current v0.13.4; upgrade to Terraform v0.13.5 or greater to work with this state
$ brew upgrade hashicorp/tap/terraform
Warning: hashicorp/tap/terraform 0.13.4 already installed
https://releases.hashicorp.com/terraform/0.13.5/terraform_0.13.5_darwin_amd64.zip