Issue
After installing the latest Heroku CLI I am still receiving warnings about it being deprecated. The error message may also be "Install the Heroku CLI from https://cli.heroku.com"
Resolution
Seeing deprecation warnings means you probably have an older install of the heroku program in your $PATH. You can check the current heroku binary from the output of the following command, when run on your (Linux or Mac) machine:
which heroku
Two possibilities are an older install via homebrew (OSX users only) or an older version of the heroku Ruby gem. You should be able to remove those with either:
brew uninstall heroku
or
gem uninstall heroku --all