Sprint today announced that it sold 5.6 million smartphones in the fourth quarter of 2013 and 20.5 million smartphones for the year. It is unclear how many of those smartphones were iPhones as the carrier is following Verizon Wireless and AT&T in not breaking down its smartphone sales or activations by platform. Sprint added 682,000 customers in the last three months of the calendar year, bringing its total customer base to 53.9 million subscribers. Total retail postpaid churn was 2.15%, down slightly from the 2.18% measured in the year ago quarter. The company reported a l
