I think if the system behaviour is a data structure then data structures can be loaded during runtime and again later on, this is a bit similar to Entity Component System, entities can come and go at runtime and be efficiently handled.

If you combine this with dynamic embedded scripting, you can have runtime systems that are completely reloadable while running. You can also decide when to serve requests with the new design and old design.

I'm trying to bring the patch to the application itself rather than at the network layer.