“Apple’s just rolled out iOS 8.1.1 for iPhone, iPad, and iPod touch. Aside from the usual promise of bug fixes and security updates, Apple says the latest release should speed things up on iPad 2 and iPhone 4S, two of the company’s aging devices.”
Read more here: http://www.theverge.com/2014/11/17/7235239/apple-ios-8-1-1-now-available-improves-performance-iphone-4s-ipad-2