According to Apple, iOS 8.1.1 will improve performance for older, A5-powered devices running iOS 8, namely the iPad 2 and iPhone 4s; Apple’s current selling iPod touch first released in 2012 is also powered by Apple’s A5 chip. The update appears to be without issue unlike the botched iOS 8.0.1 rollout.
The update is available over-the-air through the Settings app under General and Software Update. As always, you will need to be on WiFi with 50% or more battery or be connected a power supply to download and install the update.
In addition to releasing iOS 8.1.1, Apple also shipped OS X 10.10.1 with WiFi performance fixes and other improvements as well as a maintenance update for the third-generation Apple TV bringing it to version 7.0.2.