Apple released iOS 7.1 yesterday, the update involves the next things according to the documentation:

    - Improvements of Siri
    - Automatically enable HDR on iPhone 5s
    - Updated look and feel
    - See Calendar events better than ever
    - Touch ID fingerprint recognition is improved.
    - An occasional Home screen crash bug has been fixed
    - iPhone 4 users will enjoy improved responsiveness and performance

You can find more information by visting the next links:

Extra: checkout this link to the new UI Changes here

iOS 7.1