Change effective on 03 January 2019
Applications using the
heroku/ruby buildpack that do not have a version of Node installed by another buildpack (such as the
heroku/nodejs buildpack) will now receive Node version 10.14.1 and Yarn version 1.12.3.
These versions and instructions on how to specify a specific version of these binaries can be found on the installed binaries section of the Heroku Ruby Support page.