According to a source with knowledge of Apple's plans, starting on May 8th, emails will be sent out to those eligible to trade-in their older Apple iPhone, trying to get them to trade up to an Apple iPhone 5s or Apple iPhone 5c. The source characterized this trade-in as being "enormous," and will help Apple boost its iPhone revenues.
The source said that Apple is preparing its stores in all states, to handle a large number of visitors who will be looking to take advantage of the trade-in deal. Apple is instructing its stores to expect a surge in visitors on par with the numbers that invade these stores on the day that a new iPhone or iPad is launched. Apple Store managers are supposed to be alerted to its plans on Tuesday.
The Cupertino based tech titan is believed to be working on other ideas, designed to pump up iPhone sales in Apple Stores. Apple could be looking to get rid of as much inventory of its 4 inch models as possible, prior to the introduction later this year, of a larger screened Apple iPhone 6.
source: 9to5Mac via SlashGear