"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
First Magazine Advertisement for iPhone 5s Appears, Highlights Touch ID Sensor
Your finger is the password.The spot in our image includes T-Mobile branding, but Apple's iPhone TV ads have traditionally rotated branding between all the carriers that carry the iPhone, likely as part of a co-marketing agreement.
Touch ID was created not only to protect all the important and personal information on your phone, but to be so easy to use, you'll actually use it. Its state-of-the-art technology learns your unique fingerprint, so you can unlock your phone or even authorize purchases with just a simple touch.
Touch ID. Only on iPhone 5s.
Apple has been heavily advertising the iPhone 5c on television in recent weeks, but we have seen relatively little about the 5s, likely because of tight supplies. The print ads mention 'limited availability' of the iPhone 5s in fine print.
Update: Entertainment Weekly and Sports Illustrated are running the same ad but with Sprint co-branding, while Rolling Stone is running it with Verizon co-branding and TIME is running it with AT&T co-branding.