Ruby on Rails 6.0: What's New, Release History & Support Lifecycle

What Is New in Ruby on Rails 6.0

How does Rails 6.0 simplify handling incoming email?

Rails 6.0 introduces Action Mailbox, a framework for routing inbound email to mailbox classes.

Action Mailbox parses incoming messages and dispatches them to controller-like mailboxes, letting you keep email handling logic alongside your regular Rails code.

• Create a mailbox with rails generate mailbox Support.
• Configure inbound routes in config/routes.rb using mailbox :support.
• Leverage Active Storage to attach files automatically.

# app/mailboxes/support_mailbox.rb
class SupportMailbox < ApplicationMailbox
  def process
    # business logic here
  end
end

This matters if you need to process support tickets, newsletters, or any automated email workflow without pulling a separate mail server library.

What rich-text editing capabilities are built into Rails 6.0?

Rails 6.0 adds Action Text, which integrates the Trix editor and stores content in a dedicated RichText model.

Action Text lets you embed images, galleries, and formatted text directly in your models while handling uploads via Active Storage.

• Generate the RichText model with rails action_text:install.
• Use has_rich_text :content in any Active Record model.
• In views, render with form.rich_text_area :content.

# app/models/article.rb
class Article < ApplicationRecord
  has_rich_text :body
end

This is useful for blogs, CMS platforms, or any feature that requires user-generated rich content.

How can I speed up my test suite with Rails 6.0?

Rails 6.0 ships with Parallel Testing, allowing tests to run across multiple processes or threads.

By default Rails forks a number of worker processes equal to the CPU core count, dramatically reducing total test time.

• Run rails test:parallel to execute all tests in parallel.
• Use parallelize(workers: :number_of_processors) inside test_helper.rb for custom worker counts.
• Threaded mode is available via --threads flag.

# test/test_helper.rb
class ActiveSupport::TestCase
  parallelize(workers: 4)
end

Watch out for tests that rely on shared state; they may need to be made thread-safe.

What multiple-database features does Rails 6.0 provide?

Rails 6.0 adds first-class multiple database support, including migrations, schema cache, and connection-switching APIs.

This enables you to shard data, separate read-only replicas, or use different databases for legacy tables without leaving the Rails ecosystem.

• Define databases in config/database.yml with primary and replica sections.
• Run migrations on a specific database via rails db:migrate:primary or rails db:migrate:replica.
• Switch connections in code with ActiveRecord::Base.connected_to(database: :replica) do ... end.

# Example of read-only replica usage
ActiveRecord::Base.connected_to(role: :reading) do
  User.find_each { |u| puts u.email }
end

This matters for scaling applications that need to offload reporting queries or comply with data-segregation policies.