whatsnew update

dist/preview release/what's new.md

@@ -206,6 +206,7 @@
 - Fixed Path2 length computation ([Poolminer](https://github.com/Poolminer/))
 - Cloning of `ShaderMaterial` also clone `shaderPath` and `options` properties ([Popov72](https://github.com/Popov72))
 - Prevent an infinite loop when calling `engine.dispose()` in a scene with multiple `SoundTracks` defined ([kirbysayshi](https://github.com/kirbysayshi))
+- Fixed missing properties in serialization / parsing of `coneParticleEmitter` ([Popov72](https://github.com/Popov72))
 
 ## Breaking changes