Just received this e-mail:
Download the latest version of our mobile app, get 15% discount!
Dont miss the opportunity to get a special discount. Please note that
this campaign is only valid until January 20th, 2018.
TERMS & CONDITIONS
Purchasing Period: 18 - 20 January 2018 Departure Date Interval: 18 January - 31 December 2018
Ticket Type: One Way & Round Trip Cabin: Economy & Business
Discounted offer is applied to base fare, (taxes, fees, surcharges etc. will be excluded) and
subject to availability (due to limited seating capacity).
Special offer prices may change subject to currency fluctuation.
Discount is valid only on Turkish Airlines flights.
The discount amount may vary for children and infants.
Rebooking, cancelation, refund terms are subject to the fare rules of the booking class.
Turkish Airlines has the right to change promotion conditions.
Other restrictions may apply depending on route and travel dates.
For further information/assistance please contact a Turkish Airlines Sales Office or Call Center.
Of course I just tried a booking using the app (North EU to MLA in J) and the price didn't change from what I was quoted on the website two days ago...