For Minecraft mod developers, this update could also be called mob update as this update introduces many new features for mob (moving game entity in Minecraft) creation. This includes selection of game mechanics that were not supported so far, definition of particles for mobs and much more.
Many improvements regarding workspace management were made too. We have rewritten our XML workspace structure parser so it is more reliable and efficient. This will fix many bugs related to workspaces and switching between them. Mod element removal system was improved alongside with resource removal system which was not supported up to this update. Each workspace now holds its own set of resources (textures, 3D JSON model definitions, OBJ models and OGG sound files) instead of the old shared resource system which caused exported mods to contain many unused resources.
Import process was also improved so it should now be faster and more reliable and won't break any existing workspaces
The main improvement for advanced mod developers is of course the code editor. We have updated the code editor library which now supports matched bracket popups and fixes many source code editor related issues. Jump to declaration feature was introduced which activates with Ctrl + mouse clicking on selected code section. If MCreator manages to find the declaration, the file containing it will be opened on the corresponding code line. This function is still beta and only basic declarations such as this, super and class declarations are supported.