Condition 1: There must be a Rainbow 7 in the sky.
Condition 2: When upgrading, Escape button is available. (to skip animation part and can upgrade again when Elena is still upgrading your necklace).
Condition 3: Remove all equips except gloves and weapon.
Condition 4: You must have sufficient gems to upgrade.
Condition 5: The Necklace should be +6 or above.
If above conditions are met procede to step 1.
STEP1 - Upgrade Necklace.
STEP2 - Press Ecs then equip the Necklace. (This technique will actually predict the outcome of the upgrade.)
STEP3 - Repeat process until it turn to 8.
STEP4 - When upgrading to 9, upgrade it and press Esc and equip it, this time, go to other servers then go to your inventory. Repeat process until you a 9 on your Necklace. (When it degrades, repeat STEP1.)
You know I was shocked when I upgrade the Necklace to 9. Remember the Shadow Necklace bug? the one that a +8 Shadow shows 3 dark ***** spinning around your character, it was fixed. I think it help me easily upgrade it.
Sorry no Screenie for this. I actually do it in a shop with a DeepFreeze. Try for yourself. The condition 1 make sense of the upgrading thing. Right?
Credits is from Me actually. Press Thanks if I helped.
