That is not how I understood it. The year one page / section shows you what you had and allows you to delete old stuff and re acquire it at level one values later if you want. But level one stuff was all about 180 attack I think and can't be infused. So will get left behind. Year one stuff is there for reference / completeness. And so you never "lose" your year one exotics. Some exotics then carry over into the year two section and become year two weapons with different base stats and perks but can also be infused. They also explicitly said at one point that not all exotics will carry over to year two. So, can you use year one weapons in ttk? Yes. Will year one weapons get left behind (other than those that transition to year two)? Yes, but my guess is not for a while in the case of top tier current weapons. What bothers me a bit about that is it's a bit lazy. Of the "new" exotics it looks like nearly half will just be tweaked original exotics. I didn't see many new weapon perks at all. In fact I can't remember even one.