iPhone differences in different countries or carriers

Question

Is there any difference between software/hardware of iPhone 6 devices in different regions/carriers or all iPhone 6 devices around the world are exactly same from applications perspective ?

Answer 1

There are different hardware models by country / carrier to support different LTE bands. Apple has a list at http://www.apple.com/iphone/LTE/

Answer 2

Software can have also little differences. In example Japanese and Korean models cannot mute their camera sound (Over there this is done also by all the other camera and mobile manufacturers). So they have a slighty different software.

Answer 3

In addition, on devices bought in China FaceTime Audio is disabled, while FaceTime Video is available. See http://www.zdnet.com/article/facetime-audio-disabled-in-china/