Upgrading GitHub from Rails 3.2 to 5.2
There are several "we upgraded Rails, it was huge, risky, and took months to years" blog posts from medium to large companies. I personally take this as a warning against using Rails. Ruby is one of the most dangerous dynamic languages to refactor, I don't see how struggling to do it for over a year is a selling point of the framework. It also feels counter to Rails's mantra of delivering value fast with little effort, until you need to upgrade, then you have months of no business value delivery and need to bring in experts to help.