BigBinary

BigBinary is a Ruby on Rails consultancy that gives 2011 as its founding year and lists offices in Miami, Florida and Pune, India. Its upgrade service page says it has upgraded many Rails applications to the latest version, and its homepage lists maintenance, performance and team augmentation as separate services.

Its published case studies, such as Lovewick, list Rails with ReactJS and React Native in the stack. They describe new builds, not Rails upgrades alongside React. The Gumroad case study quotes the client's CEO crediting BigBinary contractors with fixing bugs and maintaining the site; it is maintenance evidence, not an upgrade.