@huoxito I think the reason that the extension didn't previously allow variants (other than master) for the product assemblies is that a product assembly is nothing other that a collection of other products to be sold as a collection... from that point of view, it is not really a product itself, just a way of selling other products together... so, if we wanted to have other 'variants' of such a product it would necessarily mean somehow altering it's collection of parts. But since association of parts exists on the products model there's no way to alter it for just one 'variant' of a product; you would need to create a new product assembly with a somehow different collection of parts (variants). Or, at least that's how I understand it.