JRuby versions 9.4.12.0, 9.4.12.1, 10.0.0.0, and 10.0.0.1 are now available

Change effective on 08 May 2025

JRuby v9.4.12.0, 9.4.12.1, 10.0.0.0, and 10.0.0.1 are now available on Heroku. To run your app using this version of Ruby, add the following ruby directive to your Gemfile.

For example:

ruby "3.4.2", engine: "jruby", engine_version: "10.0.0.1"

The JRuby release notes can be found on the JRuby website.