The Future of Burst in Unity 6.6+

Unity Engine
,
1

Hello!

Burst is moving from being a package to becoming a part of the engine itself in Unity 6.6.
This means that in Unity 6.6+ you won’t need to include the Burst package in your project, as it will be a set of built-in modules instead.
Existing projects that reference the Burst package will still work, but in Unity 6.6+ the Burst package will just redirect to the built-in version instead.
This has the side-effect that if you have a local version of the Burst package in your project, it’ll break upon upgrading and you’ll not be able to make local changes to Burst in the future.
This change also means that updates to Burst will then be released as a part of the editor, instead of a separately as has been the case up until now.
If you reference the Burst package via Packages/manifest.json, then you don’t need to do anything. If you embed a local version of the Burst package in your project, you should be prepared to remove that local version when upgrading to Unity 6.6+.

34 Likes
In Case You Missed It: February & March Edition
CoreCLR, Scripting, and Serialization Update - June 2026
Burst Release Announcements and Notes
4

Omg, finally it will stop taking disk space in every single project :distorted_face:

1 Like
5

Hi,
can you tell use why this change is happening?

I understand this might be necessary

  • Editor code running something under Burst
  • Entities integration use Burst for hierarchy window and other UI

The downside is obvious - we won’t be able to have “custom Burst”.
What are the upsides?

6

Has anyone actually modified Burst in all it’s lifetime? Sounds extremely risky and unnecessary, like 0.001% niche case

7

Anything that’s in a package can’t be used by anything built into the engine.

So if the current focus is on ECS for all, then any associated package will need to become built in.

Same reason why UI Toolkit became built in.

4 Likes
8

Right, it takes ~500MB by each copy of “libllvm” which is used by Burst internally.