Not sure if you're asking, but I'm not repeating someone else's rumor. I started the set-up I work with using hot loading (after all that is one of the things that attracts to Erlang) where I mean just reloading modules on the VM. Unfortunately I would get module order wrong from time to time or I would forget dependencies, and I've seen many badfun errors as well (I admit I used too many anonymous functions). With only 1 node doing the work (I haven't used Erlang on large clusters) that's a bit more risk and those problems have gone away completely since I switched to a strategy where the whole system just stops and starts.