Why am I seeing `certs:auto:disable is not a heroku command.`?

Resolution

This error message is shown when using outdated versions of the Heroku Command Line tools. Download and install the latest version to fix this using the instruction here https://devcenter.heroku.com/articles/heroku-cli

For users who are still having trouble, please check to see if you have the legacy heroku gem installed and follow the steps here https://devcenter.heroku.com/articles/heroku-cli#uninstalling-the-legacy-heroku-gem to remove it.