Every winter and summer, all airlines make a great amount of schedule changes. As stated earlier, they had given notice a while before, it did happen to me that my flight schedule was change few days before my depature, and only found out at the airport, My fault for giving the wrong phone number.
Did you read their Terms,
Carrier undertakes to use its best efforts to carry the passenger and baggage with reasonable dispatch. Times shown in timetables or elsewhere are not guaranteed and form no part of this contract. Carrier may without notice substitute alternate carriers or aircraft, and may alter or omit stopping places shown on the ticket in case of necessity. Schedules are subject to change without notice. Carrier assumes no responsibility for making connections.
Those terms come from the Warsaw Convention.