When I was at Google this was the single worst problem we had in engineering, at least in terms of engineer-hours consumed. We came up with a bunch of solutions, a few of which (like protobufs) are open-sourced and many of which are just in the heads of the engineers who did them, but there's unfortunately no general solution to the problem. Sometimes I dream about a programming language that has thought through all these issues and includes "evolvability" as a first-class design constraint, but oftentimes these problems show up in multi-process situations where you may be using multiple programming languages.