Apple has released iOS 7.1.2 Mail and iBeacon Improvements

Apple released iOS 7.1.2 on 30 June 2014 night 

Fixes Detail : improvements iBeacon connection ,and fixes data transfer by cable barcode reader ,and mail security attach file.

You can upgrade iOS 7.1.2 by over the air,  Going to Settings > General > Software Update and tapping Download and Install.because this upgrade easiest 

If freeze during install you can hard reset by hold down Home button and Power button ( same you take screenshot on your iDevice ) Hold both button untill the screen black off and then turn on your device again with apple logo ,after that go to setting > General > About  check your version 7.1.2 or not ,if not iOS 7.1.2 ,try to upgrade iOS 7.1.2 again