> Since the beginning, GitHub.com has been a Ruby on Rails monolith. Today, the application is nearly two million lines of code and more than 1,000 engineers collaborate on it daily. We deploy as often as 20 times a day, and nearly every week one of those deploys is a Rails upgrade. > ## Upgrading Rails weekly > > Every Monday a [scheduled GitHub Action workflow](https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#schedule) triggers an automated pull request, which bumps our Rails version to the latest commit on the Rails main branch for that day. All our builds run on this new version of Rails. Once all the builds pass, we review the changes and ship it the next day. Starting an upgrade on Monday you will already have an open pull request linking the changes this Rails upgrade proposes and a completed build. https://github.blog/2023-04-06-building-github-with-ruby-and-rails/