Heroku & Ruby Compatibility Table
In this article we will present compatibility between Ruby and Heroku across different versions. In the process of upgrading really old applications to more modern versions of Ruby we have run into a lot of these combinations.
To find more information about Heroku Ruby support check out the Heroku Ruby Support Reference page . In general, however, we suggest you to follow the Ruby Core support policy .
Heroku Stacks and Ruby Versions
Heroku stacks are the underlying operating system (OS) environments that power your applications, built on Ubuntu LTS (Long-Term Support) versions. Each stack supports specific Ruby versions, and aligning your application with the correct stack and Ruby version is critical for ensuring compatibility and avoiding deployment issues.
Heroku Stacks Ruby Version Compatibility
When a Heroku stack reaches its end-of-life (EOL), it no longer receives security updates or official support. This can impact your application’s compatibility with Ruby versions and expose it to security vulnerabilities.
Heroku announces EOL dates well in advance, giving developers time to migrate to newer stacks. Migrating often requires updating your Ruby version to ensure compatibility.
For a detailed guide on upgrading to Heroku-22, refer to Aysan’s article on FastRuby.io. .
| Feature | Heroku-20 | Heroku-22 | Heroku-24 |
|---|---|---|---|
| Base OS | Ubuntu 20.04 | Ubuntu 22.04 | Ubuntu 24.04 |
| Ruby Version Support | 2.5.x - 3.4.x | 3.1.x - 3.4.x | 3.1.x - 3.4.x |
| Security Updates | Deprecated | Active | Active |
| End Of Life | April 2025 | April 2027 | April 2029 |
| Recommended Actions | Migrate to Heroku-22 or higher | Migrate to Heroku-24 | No immediate action required. |
There’s also support for JRuby , an implementation of the Ruby programming language that runs on the Java Virtual Machine (JVM) and can be deployed on the Heroku platform.
Supported Bundler Versions
Heroku’s support for bundler versions is split based in two different Heroku Generations: Cedar and Fir . Heroku stacks 20/22 are only in Cedar, and Heroku-24 can run on either Cedar of Fir.
Cedar applications will bundle with the following versions:
| Bundle With | Install |
| 1.x | 1.17.3 |
| 2.0.x to 2.3.x | 2.3.25 |
| 2.4.x | 2.4.22 |
| 2.5.x | 2.5.23 |
| 2.6.x | 2.6.2 |
For applications running on the Fir Generation, bundler support for Gemfile.lock formats and bundler will mirror Bundler’s maintenance policy. Check the Bundler version configuration on Fir for further reference.
Need to Migrate to a newer Heroku stack?
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Feedback Wanted: Updates
If you find that this article has fallen out of date, send us message! We will continue to update this article as newer versions of Heroku and Ruby are released.