Originally Posted by f0zzyNUE

that email comes shortly before checkin opens - so it must be for your next scheduled flight ex IST. - as in other threads mentioned they rarely offer the denied boarding compensation to Elite members or business class passengers. I guess economy is overbooked and they send the mail to all passengers (not only economy class pax).
in case you booked the direct turnaround on one ticket - they need to rebook you when you miss the outbound flight from the turnaround point - if the inbound and outbound flight are on different tickets they might not help you for free and you might need to pay for rebooking incl. a no-show-fee (if ticket conditions allow rebooking - otherwise you need to buy a new ticket).