I strongly endorse having some fun with Lamdera then. Your frontend and your backend are written in Elm. Your backend state is the state of the world, and it is

I strongly endorse having some fun with Lamdera then. Your frontend and your backend are written in Elm. Your backend state is the state of the world, and it is stored in a DB. You write migrations that force you to have a safe translation between versions. They answer the question of "given a state of frontend and backend models and in flight messages, how do we construct new versions of these things?" And they can include "throw out that message" if you really want.