[yellowapple]

As a bit of a correction here to my own comment, it looks like Elixir releases don't ship with Mix, so the above example probably wouldn't work in that particular scenario (unless maybe you figure out some way to include Mix).

So the better option would be to figure out a way to compile a new release, get the modules in place where the currently-running release expects them, then write up a plug similar to the above to check for new module versions and load them (or just do it as part of whatever mechanism you'd use to get the updated modules into the running release in the first place).