I want to update my 1.17.1 survival vanilla world to minecraft 1.19 when it comes out and I can't find anywhere a way to update so that worlds don't modify existing terrain, I only want to get the new stuff in new chunks. I don't care about ugly chunk borders or anything like that, I just need a way to keep my chunks as they are right now. the closest I've seen to what I'm looking for is a small remark in here where they say:

Players who have opened a world with the Caves & Cliffs Experimental Toggle enabled when bedrock was still generating at y=0 will not receive new world generation features

but they don't go any further in the topic and searching for it I only get results for bedrock edition.

I also don't mind hopping between snapshots as long as they don't cause any nasty permanent side effects to worldgen other than what I'm looking for.

  • 1
    Does this help? How to reset chunks
    – DialFrost
    May 27 at 2:26
  • There should be something about blending data in each chunk's NBT inside the region files that tells it whether to add new stuff below or not. Changing that for every chunk manually would of course be a lot of effort, so a tool would be better. I've seen some NBT editing libraries for various programming languages, but haven't tried any of them yet. May 27 at 7:54
  • @DialFros thanks but that seems to be about deleting already generated chunks, not preserving them May 27 at 15:35
  • This is the default option. Minecraft keeps old terrain the same (other then bedrock), it simply geneerates new chunks differently and adds new buildable space below Y=0, and populates that space. Jun 15 at 4:13
  • @valkyrie_pilot the bedrock and the void below it is what i want to preserve, I want the bedrock layer to be at y=0 and nothing below it, the default is changing everything below Y=0 up to Y=-64 Jun 21 at 16:07


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