> I'm unaware of a foolproof way to share future versions aka future sources that can be programmed into deterministic code.

This is entirely possible :)

You would use an "USK" ("updatable subspace key") address of Freenet to achieve that: https://en.wikipedia.org/wiki/Freenet

Also see my other comment to the parent for an explanation of why Freenet would be preferable to blockchains here.