Obtaining a Year 2 version of an Exotic Weapon from the Blueprint kiosk is far different than having to trade in your old one to Xur just to be able to reach the next ATTACK value on it. You look like you're newish so I'll explain it to you in detail. When TDB launched, all 300 ATTACK weapons were stuck at 300 ATTACK. There was no way to increase them to the next level which was 331. Bungie wanted to have a way for us to keep our obtained Exotic Weapons so they allowed Xur to 'trade' our old 300 ATTACK versions for the new 331 ATTACK ones. This resulted in your Exotics being completely reset EXP-wise, and the process wasn't cheap by any means. Exotics took far longer to level up too back then. Bungie fixed this issue by creating Etheric Light in House of Wolves and discontinued Xur's trading-in system. Fast forward to Year 2; all of our Year 1 Exotics are pretty much useless. You can obtain a Year 2 version if the Exotic has one from the Blueprint kiosk for 150 Legendary Marks (If you've yet to obtain it) and once you have it you have it for good. You can just Infuse items into it to let it keep up with new content; similar to how Etheric Light worked but overall a better system since you didn't have to wait to obtain Etheric Light.