NotHighEnough

A datapack that increases the overworld height from -64 to 1024 blocks, for a total of 1088 blocks.

Is this datapack compatible with my world?

It should be compatible with any world, but backups are still recommended.

What happens if I remove the datapack from my world?

Any blocks above the vanilla height limit will disappear.

I get this annoying warning about experimental settings, can I turn it off?

Yes, there is a fabric and quilt mod available. See here.