JustEnoughIDs is a lightweight mod that removed the block, item, biome, potion, and enchantment ID limits by using the 1.13 chunk format in 1.12.
More specifically, it uses a blockstate palette when saving chunks to NBT, and uses an int biome array rather than a byte biome array. There should be very few incompatibilities with other mods, but in case you find one, please report it to the issue tracker. Unlike NotEnoughIDs, removing a mod is supported, and won't cause corruption of the worlds created with that mod.
Join our Discord server if you have any questions about the mod: https://discord.gg/f27hdrM
Extremely important: Removing JustEnoughIDs will break your world. It is equivalent to loading a 1.13 world in 1.12! JustEnoughIDs cannot load NotEnoughIDs worlds, see the FAQ for more details.
FAQ
Is it compatible with other mods?
JustEnoughIDs is incompatible with The Lost Cities for the moment until hopefully the next release.
However, due to the way the biome array works in 1.12, some mods may need custom support. For example, a biome may show up as "Mod doesn't support extended biome IDs -- Report to JEID" in the F3 screen, or a command may not work properly. Modded worldgen is supported, so there will never be biome ID shifts in your worlds. Please report any problems on the issue tracker such that it they can be fixed as soon as possible.
If I install JEID, will my old worlds still work?
Yes, they will. Chunks will be updated to 1.13 format as they are loaded.
Can I convert my NEID worlds to JEID?
No, not yet. However, using both NEID and JEID is possible. In that case, JEID's block and item limit fixes will be disabled, letting NEID handle those, and only the biome limit fix will be enabled, allowing you to maintain compatibility with previous worlds and still use as many biomes as you want.
Won't this mod corrupt my world?
No, this is NotEnoughIDs done properly. Just because NotEnoughIDs failed at implementing a safe system of extending ID limits doesn't mean that it's not possible. Mojang did it in 1.13 and this mod only backports features from the 1.13 chunk format to 1.12. Please don't claim that this is a "bad mod" only because NotEnoughIDs was.