Cavern link (v1.x, from 1.10.2 to 1.12.2) :
https://minecraft.curseforge.com/projec ... tID=244301
Cavern II link (v2.x, only 1.12.2) :
https://minecraft.curseforge.com/projec ... tID=285628
kegare described the difference between both :
Because here are in the same time Cavern I & II for 1.12.2 ^^Attention !
This version [Cavern II for 1.12.2] has no compatibility with version 1.x.
If you were using a old one, you must start in a new world.
PS : I know it's a lot of work, that's why I will understand if the project will take time to be ready