"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Launches Exchange Program for 5W European USB Power Adapter
The affected adapters, which are identified as Model A1300, originally came with iPhone 3GS, iPhone 4, and iPhone 4S models that shipped from October 2009 to September 2012. Apple is allowing users to bring in the affected adapters to an Apple Retail Store or participating Apple Authorized Service Provider, and will give a new adapter after a corresponding iPhone serial number is verified.
The program differs from Apple's third-party USB charger takeback program, which launched last year in over thirty countries. That program allows users to trade-in a third-party USB charger for a discount on an official Apple charger, and was created following the electrocution of a Chinese woman that may have been caused counterfeit iPhone charger.