Diablo IV · Progression system
Barbarian skill upgrade slots
The source describes a selection structure for active skill upgrades: one major upgrade and two minor upgrades chosen from separate pairs.
How it works
According to s2, each active skill can equip one Major Upgrade and two Minor Upgrades total. Minor Upgrades are divided into two in-game pairs, and a player can select only one option from each pair. This establishes the choice structure for the Barbarian upgrades listed in the same source; the passage does not describe respec rules or individual upgrade costs.
Read the supporting references
Check the edition and source version for patch-specific details. Guide methodology.