Unity 6.3 LTS arrives with hybrid 2D/3D scenes, Box2D v3, and cross-platform toolkit

Unity 6.3 launches as a Long Term Support release with two years of updates and is now the recommended baseline for new projects. It strengthens hybrid development by enabling 3D rendering inside 2D scenes through the 2D Universal Render Pipeline, allowing Mesh Renderer and Skinned Mesh Renderer elements to work alongside sprites. The 2D toolset also gains improved rendering, physics, and asset analysis features.

The update integrates Box2D v3 with new low level 2D physics application programming interfaces that improve multithreaded performance, determinism, and debugging across both the Editor and Runtime. A new Platform Toolkit unifies common cross platform tasks such as account handling, save data, and achievements under one application programming interface, easing multi platform development.

Shader Graph now supports custom lighting, terrain shaders, up to eight texture coordinate sets, and a template browser. Shader Build Settings help reduce compilation time by allowing developers to exclude or convert shader keywords without extra coding. Additional improvements include the Sprite Atlas Analyser for spotting inefficient sprite packing, customizable toolbars, better diagnostics for rendering and physics workflows, and expanded Android XR features such as face tracking, object trackables, and dynamic resolution.