The apartment was good.
It had the same problems that you can find in the apartments that are located in the old buildings of Beyoglu neighborhood, but overally, it's ok.
The host fixed our shower instantly, and made sure that the apartment is clean upon our arrival.
It had some basic amenities (hair dryer, dishes, kettle and gas stove), had good heating and hot water.
It was actually pretty hot in the apartment, but you can change boiler's temperature yourself.