»HCP Consul Version Upgrade
You can upgrade your Consul Cluster using Terraform. HashiCorp will automatically upgrade your Consul Clusters to fix Common Vulnerabilities and Exposures (CVE). Hashicorp will send an email notification once the upgrade is complete. There is no anticipated downtime for these upgrades. Once the entire fleet is upgraded to the latest patch release, only the versions with CVE fixes will be made available for selection. Prior to creating a Consul server cluster, please check the UI for the list of available versions.
Downgrading an existing Consul Cluster to earlier version(s) is not supported.
»HCP Consul Size Upgrade
HCP Consul offers two production tiers (Standard, Plus). Each of these tiers offer multiple Consul Cluster size (Small, Medium, Large). You can upgrade your Consul Cluster size within a tier using Terraform.
Downgrading size is not supported.