KLM today sent me cancellation notices for flights later this year and early next year.

However, the flight times (both departure and arrival), flight numbers, and aircraft types are identical.

And then it dawned on me - it's because the flights are now to/from Berlin (BER) rather than to Berlin (TXL).

The new airport is scheduled to open between late October and early November, with airlines moving on different days. It looks like this time it will actually happen!