The item upgrader mod Upgrader in World of Warcraft
The War Within introduced two gear upgrade items currencies, Valorstones and Harbinger Crests. These can be exchanged at the item upgrader NPCs, Cuzolth and Vaskarn.
Each item upgrader kit upgrade (https://dokuwiki.stream/) can be upgraded to its maximum level once for a slot. Then upgrades to the slot will be less expensive. The pity system, introduced with The War Within, also lowers the extreme upgrade variance.
Upgrades
Upgrades are components that improve performance or add new functionality. They can be purchased or earned through various ways, including in-game events as well as from cash shop items.
As opposed to enchantments that can be applied to any item, upgrades are tied to specific items and can only be applied to the items. Therefore, an upgrade can only be applied to a weapon when it already has been equipped by the player. However, certain items can be upgraded many times, providing a much greater benefit to the wearer of the Best item upgrader.