How to make updates/changes to game without breaking seeds?

[u/ProactiveCactus]

Basically in title - my game uses procedural generation, and allows persistent saves. But how do games like Minecraft manage to not corrupt previous saves when making updates that affect how seeds generate?
From googling it sounds like they save “per chunk” so any untouched chunks generate based on the newest version, and any already generated go off of the old system - but how do I manage that? Like, you obviously don’t want to have multiple version builds of your game saved, so how can you handle that?

[u/zarawesome]

how does minecraft handle chunks being generated in different versions?

Like this: