How to update Heroku?

You have to run

heroku update

in the terminal to update the CLI.

If that doesn't work, this means you have the CLI app as an npm or an apt package, in that case you have to runapt installation:

sudo apt-get update && sudo apt-get upgrade heroku

npm:

npm upgrade -g heroku

yarn:

yarn global upgrade heroku

Refer to the article here for more information.

CodeHunter