Europe’s Airbus says it will postpone the delivery of 12 A380 superjumbos to Dubai’s Emirates Airline.

Six aircraft deliveries will be moved from 2017 to 2018 and another six aircraft will be delivered in 2019 instead of 2018.

In November, Emirates said it had concerns over the Rolls Royce engines that have been ordered to power the A380 aircraft.

Also in November, Emirates’ Airbus fleet became all-A380 following the phase-out of three A330-200 and one A340-300 Airbus planes. The airline had 85 A380 in-service planes, with 57 pending delivery.

The delay to the A380 orders is the latest setback for the aircraft in the region. Iran Air decided to exclude the A380 aircraft from its order with Airbus when it reduced its total order from the manufacturer from 118 to 100 planes

That deal now covers 46 A320s, 38 A330s and 16 A350 XWB aircraft. Deliveries will begin in early 2017.