Default Help unrooting my mini

I have rooted my HTC one mini and now I wanna update to the newest version so I need to unroot an i have no clue what to do. I followed this guide to root in the phone in the first place:rootwiki.net/en/android-root-anleitungen/482-htc-one-mini-root-tutorial

I live in Denmark so I guess I need European version?

Aney help would be appreciated