When we were trying to deploy the rails application to the Heroku cloud we got into this error. The error is self-descriptive. The app we created on the Heroku cloud was: heroku-18. This is the stack that Heroku uses and behind the scene it uses Ubuntu-18.
Heroku cloud has another stack as of this article. The stack is heroku-16 and it uses Ubuntu-16 behind the scene.
Reason of the error
The rails app we were trying to deploy on Heroku was built with the stack heroku-16. But we were trying to deploy on the stack heroku-18. As soon as we tried to deploy we got the error:
remote: ! The Ruby version you are trying to install does not exist on this stack. remote: ! You are trying to install ruby-2.3.1 on heroku-18. remote: ! Ruby ruby-2.3.1 is present on the following stacks: remote: ! - cedar-14 remote: ! - heroku-16
Solution of the error
We had to change the stack using the following command in Heroku.
heroku stack:set heroku-16
This allowed us to change the stack to heroku-16 and we were able to deploy our app to Heroku nicely.