For now the program is only available to customers in the United States.
Here's how it works...
Customers are free to choose the carrier and rate plan that they choose but they must accept a two year installment agreement. After 12 installments, you can get a new iPhone and start a new iPhone Upgrade Program. No more waiting for your carrier contract to end. Just trade in your current iPhone for a new one, and your new program begins.
The iPhone you receive will be unlocked, letting you easily select a new carrier or stick with the one you have.
The 16GB iPhone 6s has monthly payment of $32.41; whereas, the 16GB iPhone 6s Plus has a monthly payment of $36.58. You can see the monthly payment amounts for various devices in the image below.
The iPhone Upgrade Program also comes with AppleCare+ included, giving you two years of hardware repairs, software support, and coverage for up to two incidents of accidental damage.
You can make a reservation online, starting at 12:01 a.m. PDT on September 12, to buy an iPhone 6s through the iPhone Upgrade Program in store.