Read more about Toolbelt 4.0 plugins here.
Note: These Node.js plugins are available in the current Ruby CLI. No need to download a separate Toolbelt 4.0 CLI.
$ heroku plugins:install heroku-status
$ heroku status === Heroku Status Development: No known issues at this time. Production: No known issues at this time.
or, if there were a real incident...
$ heroku status === Heroku Status Development: Yellow Production: Yellow === Increased Platform Latency 7:04:22 PM UTC 7:04:22 PM UTC (42 minutes ago) [Issue] We are experiencing a network connectivity issue with our upstream provider. We will post another update as to the status in an hour if not sooner.