I found out about this today.
I have a booking VIE-MXP for 30th December returning 2nd January with Niki. Last week airberlin/Niki sent me an e-mail advising me of a change of times, but the airport is shown as the same. However, when I checked my booking on their website, it clearly shows that they've changed the destination airport to LIN.
Now, this might be better but I've already booked a room at a hotel for 1 night near the airport at MXP! Unfortunately, this is a non-refundable booking so I won't get my money back for cancelling it. So I'm not very happy. Will airberlin pick up the bill for the night in a hotel??