Apple releases iOS 8.1.1; update adds speed to the Apple iPhone 4s and Apple iPad 2
Previous issues, such as one that affected iCloud Drive and iWork for iOS, are repaired. This should be a quick download and installation for those iOS models that are receiving the update. That includes the Apple iPhone 4s, Apple iPhone 5, Apple iPhone 5c, Apple iPhone 5s, Apple iPhone 6, and Apple iPhone 6 Plus. All iPads will receive iOS 8.1.1 except for the OG Apple iPad; the fifth-generation Apple iPod Touch also will receive it.
While the update is being sent out OTA, you can try to pull it out of your device by going to Settings > General > Software Update. You might want to make sure you are connected to a Wi-Fi network when installing the update, even if it is lightweight. Also, keep your battery charged to at least 50% to make sure that your phone doesn't turn off before the update is completed.
source: ArsTechnica via TechCrunch