https://www.polygon.com/2018/4/27/17292166/destiny-2-exotic-masterwork-catalyst-upgrade

Destiny 2: Warmind is expanding on the upgrade feature for legendary weapons that developer Bungie introduced in January — with a system to improve exotic weapons as well, the studio announced this week.

Like legendary weapons and armor over the past few months, each exotic weapon in Destiny 2 will be getting its own Masterwork version through a “catalyst.” But these new upgrades will do more than just track kills and spawn orbs. (To be clear, exotic Masterworks will be available for all Destiny 2 players, not just those who buy the Warmind expansion.)