TL;DR

Three.js now includes a new DevTools suite (browser-based debugging tools) and improved Global Illumination (realistic lighting) with position-dependent diffuse lighting.

Breaking

• Remove deprecated instancing render paths. (Older methods of instancing meshes are no longer supported.)

New

• DevTools: New browser-based tools for inspecting and debugging three.js scenes.
• Position-Dependent Global Illumination: Improved lighting realism with light probes.

Fixes Worth Knowing

• Fixed issues with timeScale on animations causing jumps.
• Corrected color handling in BatchedMesh and InstancedMesh.
• Resolved regressions affecting anisotropic materials and texture loading.
• Improved stability and performance of Node-based materials.
• Fixed issues with copying object pivots.

Before You Upgrade

• If you are using deprecated instancing methods, update your code to use the current instancing approach.