With Elixir/OTP there would be no disconnection/reconnection. The way hot code push works with OTP is that each "channel" (OTP "process"/websocket connection) has a GenServer, which is basically a state machine, and when there is a new version of the function available in the VM, the current state is passed into a function (supplied by you) to mutate it into a shape compatible with your new change, then next time the data is passed around the loop to the state management function, it goes to the new one instead. Because the state data is stored quite separately to the actual functions who mutate it, there is no need to disconnect or do any mass purging of memory when there's a hot code deployment.

If you look at the server implementation, the client messages are also read and parsed, but are not printed to stdout for demonstration purposes (otherwise it hard to keep track) You can uncomment that printf instruction and see that it still performs nearly the same way

I did hot code upgrades on a server with WS connections active and I don't remember connections being broken.