Here is one source:
The upcoming release r155 will contain a major change in context of lighting. The legacy lighting mode will be disabled by default which affects all light intensities and how point and spot lights decay. What does that mean for me? The release changes the default of WebGLRenderer.useLegacyLights from true to false and also deprecates the property. Meaning it will be eventually removed from the engine with r165. Setting WebGLRenderer.useLegacyLights to false is one important prerequisite for a…