[sb8244]

You could totally do this with BEAM, via hot swapping. The WebSocket processes don't really change, it's the implementation of what happens when messages comes in that changes. So you'd setup your hot swap with this in mind. (The connection processes stay connected and the behavior module is swapped out?)

However, hot swapping is not super common in practice. Mainly because it's added complexity that most people can live without.

[clone1018]

Right, this is the comment I was going to make as well. It's certainly possible, but there's tradeoffs (mainly around complexity) to code hot-swapping. We haven't implemented it because restarting servers to upgrade code helps everyone prepare for when servers go down for unexpected reasons, or so I like to think :P!