Your flight would most likely be operated by 'Privilege Style' on their 777 EC-MIA:
https://www.flightradar24.com/data/aircraft/ec-mia
I've only seen their C cabin and it's like the old Asiana (iirc the plane came from Asiana) or Sri Lankan.
You can try to rebook (for free) due to the equipment change. Folks on the German Vielfliegertreff (VFT) reported success in that case.
AB has a pretty bad track record over the last months when it comes to punctuality, equipment changes and cancellations due to financial problems, service provider changes (e.g. at TXL) and shortage of staff.