All the purple items should either have an expanded upgrade tree so we can upgrade them to the new damage lvl cap or simply brought to new damage lvl cap when the expansion dropped. the shops in the tower should offer the old and the new legendary guns for sale. so far no body has a good explanation why Bungie is limiting the content and the potential of their game like this. they gave new guns but removed old guns, you can buy materials now but you no longer able to sell them?