According to current media reports, the insolvent Air Berlin can only keep up its flight operations until the end of October. Later flights may be operated by leasing contractors. This might be a consequence of the complicated negotiations with Easyjet.
The information for passengers on the website have not been updated yet (09.10.2017). In a letter to the employees, CEO Thomas Winkelmann stated that more information will be available in the next few days.
Up until now, Air Berlin wanted to stop all long-distance flights until mid-October and keep doing short-distance. We recommend all consumers who booked a flight to contact the airline asap. Speaking from experience, it may take some time to get a response.