8 Costly Ruby on Rails Upgrade Mistakes to Avoid in 2025

Ruby on Rails has been a favorite among developers for years. This is due to its elegant syntax, robust ecosystem, and rapid development capabilities.

However, as with any technology, staying up-to-date is crucial. Upgrading your Ruby on Rails application ensures better performance, security, and access to the latest features.

But upgrading isn’t always smooth sailing. If you’re planning to update the Ruby version or migrate to the latest version of Ruby on Rails, here are 8 costly mistakes you’ll want to avoid in 2025.

1. Skipping Compatibility Checks Before Upgrading

One of the most common mistakes developers make is jumping straight into an upgrade without checking compatibility. Whether you're planning to update Ruby gems or upgrade the gem version, skipping this step can lead to broken dependencies and unexpected errors.

Before starting the upgrade process, ensure that all your gems are compatible with the Ruby updated version or the new Rails version. You can use bundle outdated to identify outdated gems and check their documentation for compatibility notes. Additionally, running bundle install after updating your Gemfile can help catch issues early.

Tools like RailsUp can help you check the gems compatibility instantly.

Pro Tip: Always review the release notes for both Ruby and Rails versions to understand breaking changes and deprecations. Refer here for the Rails 8 release notes.

2. Ignoring How to Update Ruby Version Properly

Updating Ruby itself is often overlooked, but it is just as important as updating Rails. Many developers assume that simply installing the latest version of Ruby will suffice, but there’s more to it than that.

To check the Ruby version, run:

ruby -v

If you need to update the Ruby version, consider using a version manager like rbenv or rvm. These tools allow you to switch between Ruby versions seamlessly. For example:

rbenv install 3.2.2

rbenv global 3.2.2

Once installed, don’t forget to update your .ruby-version file if applicable. This ensures consistency across environments.

3. Not Testing Your Application Thoroughly

Testing is non-negotiable during a Ruby on Rails migration. Even minor updates can introduce subtle bugs that might not surface immediately. Running your test suite before and after the upgrade helps identify issues early.

Make sure your tests cover critical parts of your application, including edge cases. If you don’t have comprehensive tests yet, now is the time to invest in writing them. Tools like RSpec and Minitest are excellent choices for ensuring your app behaves as expected post-upgrade.

Remember: A failing test is cheaper to fix than a production outage caused by untested code.

4. Overlooking Database Schema Changes

When upgrading Rails, database schema changes are often required. Failing to address these changes can result in data loss or corrupted records. Always review the Rails migration guides for instructions on handling schema updates.

For instance, when moving to Rails 7 from an older version, you may encounter changes in Active Record behavior or new conventions for migrations. Run rails db:migrate:status to verify pending migrations and apply them carefully.

Additionally, back up your database before making any changes. This simple precaution can save you hours (or days) of headaches if something goes wrong.

5. Ignoring Deprecation Warnings

Deprecation warnings are like yellow traffic lights—they signal that something is about to change, and you should prepare accordingly. Ignoring these warnings can lead to broken functionality when you finally upgrade.

Before upgrading, take the time to address any deprecation warnings in your logs. For example, if you see messages about methods or configurations being deprecated in your current Rails version, refactor your code to align with the recommended practices. This proactive approach will make the transition smoother and reduce technical debt.

Tip: Use tools like rails zeitwerk:check to identify autoloading issues that could cause problems in future Rails versions.

6. Rushing Through the Process

Upgrading Ruby on Rails isn’t something you should rush. Each step—whether it’s how to update ruby, upgrade gem version, or test—requires careful attention. Trying to complete everything in one go increases the risk of missing critical details.

Instead, break the process into manageable chunks:

1. Start with updating Ruby.

2. Then move on to updating Rails.

3. Finally, tackle gem updates and migrations.

By taking a phased approach, you reduce complexity and make troubleshooting easier if issues arise.

7. Forgetting About Deployment Considerations

Even if your local environment works perfectly after the upgrade, deployment can still fail due to differences in server configurations. Ensure your production environment matches your development setup.

Here’s what to double-check:

• Is your server running the correct Ruby updated version?

• Are all necessary gems installed and compatible?

• Have you updated your CI/CD pipelines to reflect the new versions?

Tools like Docker can help standardize environments, reducing the chances of discrepancies between development and production.

8. Not Having a Rollback Plan

Even with meticulous planning, things can go wrong during an upgrade. That’s why having a rollback plan is essential. Without one, you risk extended downtime or irreversible damage to your application.

Here’s how to prepare:

• Backup Everything: Ensure your database, codebase, and configuration files are backed up before starting the upgrade. Current environment variables and secrets should also be documented.

• Version Control: Make sure your Git repository is clean and all changes are committed before proceeding.

• Staging Environment: Test the upgrade in a staging environment that mirrors production as closely as possible.

• Quick Revert Strategy: Know how to revert to the previous version quickly if needed. This might involve redeploying an older build or restoring a database snapshot.

Final Thoughts

Upgrading Ruby on Rails isn’t just a technical task, it’s an opportunity to breathe new life into your application. By avoiding these nine costly mistakes you’re not only safeguarding your codebase but also setting the stage for innovation and scalability. Think of it as giving your app a fresh coat of paint while reinforcing its foundation.

But here’s the thing: upgrades are rarely a one-and-done deal. The tech world moves fast, and staying ahead means adopting a mindset of continuous improvement. Whether it’s mastering how to update the ruby version, addressing deprecation warnings, or preparing a solid rollback plan, each step forward is a chance to learn and grow as a developer.

As you embark on your upgrade journey, remember that perfection isn’t the goal—progress is. Don’t let fear of breaking things hold you back. Instead, lean into the process with curiosity and resilience. And if you hit a roadblock? Reach out to the RailsFactory—you’re never alone in this.