Apple will give customers a credit for their old phones to be used toward the purchase of a new model, an Apple spokeswoman said.
A thriving industry exists for older versions of smartphones, especially the iPhone, on websites such as eBay and Gazelle. Even broken iPhones can fetch as much as $125 from vendors, who resell them in the United States and internationally.
Gazelle Chief Executive Israel Ganot estimated the used smartphone and tablet market in the United States will reach $14 billion by 2015.
"So there's obviously a huge opportunity here for multiple players," he said.