Intercom has been running on Rails since 2011. Starting from Rails 3.0, today our 3 million line monolith is running on the main branch of Rails. This talk covers our Rails upgrade journey over the last 15 years - the things that broke, the monkey patches keeping it all together, and what it takes to get 300 engineers comfortable shipping on unreleased Rails versions.

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Iliana is a Senior Product Engineer on the Datastores team at Intercom. She upgrades Rails for a living and has the monkey patches to prove it. Her team owns the databases and frameworks that Intercom is built on, and in between keeping hundreds of engineers shipping, she has contributed fixes upstream, mentored engineers, and migrated billions of rows to PlanetScale. When she’s not chasing deprecation warnings, she’s chasing marathon finish lines or helping organise Ruby meetups in London.