Thanks YVan.
I see.
However, I suppose that Steinberg::Vst::PresetFile class also may need to be updated if a plugin can implement these 2 interfaces.
It seems that PresetFile class doesn’t have APIs to distinguish whether the stored data of ChunkType::kProgramData is from IUnitData or IProgramListData.
So if I read a .vstpreset file with PresetFile class that the file contains unit data or program list data of a plugin which implements these 2 interfaces, I can’t determine which interfaces, IUnitData or IProgramListData, should restore the preset data.
Sincerely,
hotwatermorning