iOS 8.1.1 is appearing on iPhones, iPads and iPod touches around the world via the standard over-the-air update process



From TUAW:

While there's no big info about what has been fixed and/or enhanced in 8.1.1, the update notes do say that performance improvements are specifically for the iPad 2 and iPhone 4s. As of publication time, information on the security content of the update was not yet available. It will be available soon at http://support.apple.com/kb/HT1222

  iOS 8.1.1 is here, full of bug fixes, stability and performance enhancements