I’ve had a couple of people mention that they have not updated to iOS8 because they don’t have enough space on their iPhone/iPad, well the good people at MacWorld have released a step by step video that shows how to use iTunes on your Mac to do the update.

http://www.macworld.co.uk/how-to/iosapps/how-update-iphone-ipad-ios-8-without-deleting-3451992/