shadowfacts.net/site/tutorials/forge-modding-1112/updating-to-1112.md

metadata.title = "Updating to 1.11.2"
metadata.date = "2016-11-27 09:48:42 -0400"
metadata.series = "forge-modding-1112"
metadata.seriesName = "Forge Mods for 1.11.2"

If you're updating from 1.10.2 to 1.11.2, there are a couple of things you need to be aware of:

ItemStacks are never null

Starting in 1.11, ItemStacks can never, ever be null. Instead of checking for null-ness, you use the ItemStack.isEmpty method to make sure the stack contains something.

ItemStack private fields

In 1.11, the ItemStack.stackSize field was made private. Instead of directly modifying this field like before, there are getter, setter, and mutator methods available.

• getCount: equivalent to simply retrieving the field.
• setCount: equivalent to setting the field
• grow: equivalent to increasing the field. stack.grow(1) is equivalent to stack.stackSize++.
• shrink: equivalent to decreasing the field. stack.shrink(1) is equivalent to stack.stackSize--.

Note: The default Forge MDK comes with older MCP mappings in which the new ItemStack methods aren't named. You'll need to change the mappings version from snapshot_20161111 to the latest (snapshot_20170330 as of this post).

Resources

In 1.11.2, Minecraft enforces all resource file names being completely lowercase. This practically enforces snake_case instead of camelCase. You'll need to rename all your resource files (blockstates, models, textures, etc.) and change all the corresponding uses of their old names in code.

Other

Aside from those major changes, there are a couple of minor things:

• CreativeTabs.getTabIconItem returns an ItemStack, not an Item now.
• Various mapping changes throughout the MC codebase. You can search on here to see mapping changes in 1.11.2.