Apple released the iPhone 4

On 24/06/2010, Apple Inc. officially released the iPhone 4 in the United States, the United Kingdom, France, Germany, and Japan, marking the fourth generation of its smartphone lineup. The device had been unveiled earlier by Steve Jobs during Apple’s Worldwide Developers Conference on 07/06/2010 in San Francisco. Pre orders began on 15/06/2010, and Apple later announced that more than 1.7 million iPhone 4 units were sold during the first three days of availability across the initial launch markets. The iPhone 4 introduced a redesigned exterior featuring a thinner profile, stainless steel band, and aluminosilicate glass panels on the front and back. It also debuted the Retina display with a resolution of 960 by 640 pixels at 326 pixels per inch, which Apple said made individual pixels indistinguishable at typical viewing distance. The device included Apple’s A4 system on a chip, previously used in the iPad, enabling improved performance and battery efficiency compared with the iPhone 3GS. Apple also introduced FaceTime video calling with a front facing VGA camera, allowing Wi Fi based video calls between iPhone 4 devices at launch. The rear camera was upgraded to 5 megapixels with LED flash, backside illumination sensor, and 720p HD video recording at 30 frames per second. The phone shipped with iOS 4, which added multitasking for supported apps, home screen folders, unified email inbox, and the iBooks application with access to the iBookstore. The initial launch saw strong demand, with many Apple retail stores and carrier outlets reporting limited stock on release day. The iPhone 4 was offered in black at launch with 16 GB and 32 GB storage options, while the white model was delayed and released later in April 2011. The device became one of Apple’s fastest selling iPhone models at the time of its introduction.