Information from Etihad about Terminal A:
"1 - 8 November: All Etihad Airways flights will arrive and depart from Terminals 1 and 3.
9 - 14 November: Our move begins. If you’re flying with us during this time, please check your terminal information carefully within 72 hours of your flight.
14 November: We’ve moved! From 11am on 14 November, all Etihad Airways flights will operate to and from Terminal A."
https://www.etihad.com/en-gb/fly-eti...-a-information