FaceTime call notifications are now synced via iCloud, so that they are automatically wiped on all devices when you answer a call, and the iPhone 5s’ camera can now be set to take HDR photographs automatically. There are also new ‘more natural sounding male and female voices’ for Siri in various languages, including UK English. And in Calendar, Events are now displayed in Month view.
There is a noticable speed increase as well when jumping in and out of applications, random crashes have apparently been fixed and subtle changes have been made to the user interface. A worthy update and as others have commented, 6 months overdue.
On your iPhone and or iPad, go to Settings, General, Software Update to commence the update if it hasn’t already prompted you to.