in update will infusion erase upgrades?
No. I can confirm. You will have the same AR you had before update. Anything that had inherent AR is now in the new slot.
For example An infused ring before was :
-Agony resist on ring + 5
-Infusion slot, Agony Resist +5
Now, post -patch the same ring has this :
-New Agony Infusion slot, Agony Resist +5
-Same old Infusion Slot, Agony Resist +5
Just how it is on the gear has changed. You lose nothing.