The iPhone 4s was Apple's fifth-generation smartphone, announced on October 4, 2011, and notably served as the final product unveiled during Steve Jobs' lifetime, as he passed away the following day. It launched on October 14, 2011, in several major countries, achieving record sales of over one million units in the first 24 hours of pre-orders and four million within the first four days of retail availability. The "s" in its name stood for Siri, an intelligent personal assistant that debuted exclusively on this model, alongside major internal upgrades like the Apple A5 chip, an 8-megapixel camera with 1080p video, and the new iOS 5 operating system featuring iCloud and iMessage. Reviewers praised its processing speed, camera, and Siri, though some were disappointed it wasn't the rumored "iPhone 5." It was succeeded by the iPhone 5 in September 2012, and officially discontinued in September 2014, though production for developing markets continued until February 2016. Notably, it was the last iPhone to use Apple's 30-pin connector and the first to support five major iOS versions (iOS 5 through iOS 9).