I’m not sure what exactly you’re disputing. I would wager that nearly everyone who has run Erlang code in production has upgraded code (edit for precision: a m

I’m not sure what exactly you’re disputing. I would wager that nearly everyone who has run Erlang code in production has upgraded code (edit for precision: a module) live. To engineer the entire application to support an upgrade, and to do all the testing required to make sure it will work correctly, is very resource-intensive, and (lacking real numbers, just from observing the industry working for Basho) I’d wager very few people do so.