My theory is that there are plans for a system that has not yet been announced in any way(and we don't even know what stage it is at yet) . So it is as follows:
ANKA-S - piston engine, medium altitude, 350kg payload, 30 hours mission endurance
ANKA II - AKSUNGUR - piston engines, medium altitude, >750kg payload, 60 hours endurance
ANKA II/B - GOKSUNGUR - Turboprop / Turbofan, High altitude service altitude, <2000kg payload, 36 hours mission endurance
STEALTH UAV/S-IHA (currently under development) - Turbofan, internal weapon station, >4000 km combat radius, <3000 ft/min climb, <2000 kg payload, <12-hour mission endurance
STEALTH UAV II/TISU (Future) - Turbofan, internal weapon stations, more less operatinal radius, >3000 ft/min climb, >2000 kg payload, 4/6-hour mission endurance
(none of this information is official, I am just making guesses by comparing with old documents)