In each version of GS, a lot was removed or added. That makes Existing worlds changing over and over , especially ores and generated blocks.

So is there any possibility that there is little change in existed worldgen, block, item, biomeID and registry, dimensionID, enchantmentID in GS 1.2.1, 1.2.2 ...? You could add more of these things(please do so), but please change little in existed ones.

Recipes and new Systems(say travel system) are free to change any time.

I know this is hard to do. One project I hold is Chisel, which has a lot of branch. I must make worlds with the mod compatible with any branch.