Each minor release of Rails brings shiny new features and mild headaches for developers required to upgrade their applications and gems. Rails 5.1 will support Yarn and modern Javascript transpilers, remove jQuery from the default stack, integrate system testing and a concurrent test runner, introduce a new helper to create forms, provide encrypted secrets and more. In this talk, I will cover the improvements brought by Rails 5.1, explain the Core team’s motivations behind each feature, and illustrate the upgrade process to smoothly transition gems and apps from Rails 5.0 to Rails 5.1.