Season 15 item upgarde from +10 to +15 can be made in Equipment Reinforcement combination tab.
TIP 1: To Reinforce an Item from +10 to +15 you will need:
- 21 Jewel of bless and Jewel of soul,
- 6 Jewel of Chaos.
TIP 2: To protect your item that you want to Reinforce, use Talisman of Chaos Assembly. In case of failure you wont lose your item.