/application only sees the most recent available version of the runtime environment that it can run against/ Please, never implement something like this. It's

/application only sees the most recent available version of the runtime environment that it can run against/ Please, never implement something like this. It's hard enough to validate an app against one set of software versions. I can't think of a single time when implying forward compatibility worked right. DLL Hell on windows, and any time your libraries got upgraded while in the middle of a dev cycle in maven, just makes things hurt. Just let the application's metadata (e.g. jar manifest) indicate what it wants, and give it exactly that. If we want efficiency, we'll delta-encode different versions against each other. When automated testing is implemented widely enough, and well enough, for us to trust forward compatibility without human intervention, then we can go down that route.