If you buy a device or receive a service part replacement outside of Turkey
If you start using your iPhone, iPad (Wi-Fi + Cellular), or Apple Watch (GPS + Cellular) on a mobile network in Turkey, you might get an alert from BTK saying that your IMEI isn't registered. BTK is the Information and Communication Technologies Authority in Turkey.
To register your IMEI, go to the e-government website of the Republic of Turkey. If you don't register, you'll have no access to mobile networks in Turkey. The status bar on your iPhone or iPad (Wi-Fi + Cellular) will show No Service.
Learn more at BTK frequently asked questions.
If you buy a device or receive a service part replacement in Turkey through an Apple-authorized channel
Apple will register the IMEI of your iPhone, iPad (Wi-Fi + Cellular), or Apple Watch (GPS + Cellular) on your behalf.