https://www.polygon.com/2018/8/7/17661380/destiny-2-forsaken-weapons-masterwork-mods

Bungie finally shed some light on the revamped weapon customization system for Destiny 2 in a livestream Tuesday. While no new weapon systems are coming in Destiny 2: Forsaken, the studio is seriously overhauling the Masterwork and mod setups from the base game.

All weapons will now have Masterwork levels, up to tier 10. Each time the level is raised, the weapon’s Masterwork stat will go up by a single tier. The first few levels are relatively cheap to increase, only taking a handful of Glimmer. However, to reach tier 10, players will need to invest Legendary Shards and Masterwork Cores into their weapons.