How to safely activate LTE on S4 mini (GT-i9195) running 4.2.2?

I'd like to activate LTE on my device: [S4 mini with LTE (GT-i9195)](http://en.wikipedia.org/wiki/Samsung_Galaxy_S4_Mini) . There seems to be ways of doing this, but they seem rather "scary" and experimental at best: - http://www.androidauthority.com/community/threads/how-to-activate-4g-lte.16160/ - https://android.stackexchange.com/questions/1468/do-you-know-other-android-keypad-commands-dialer-codes - http://forum.xda-developers.com/showthread.php?t=2734094 Is there are a better or "official" way of activating LTE on this device??