Mi2S update issue

Jul 10, 2014

I am a proud owner of Mi2s 32gb, however, it seems it just never updates (and I mean really never). Whenewer check for update is being one trough an updater app, MIUI just returns @You already run the last version bla bla bla@, but it's just not true as my Mi3 pulls updates like it'll never stop, while Mi2s have never updated (one year!!!).
It says, Android 4.1.1 JRO03L, MIUI-3.10.11.
Themes are no longer working, so I suppose the third party I bought it from have put some off the record ROM up there that lost it's way to server. I would really like to update the device, but I do not know how.
Anything that could compromise my contacts, messages and other data is out of the question, but please instruct how could I update it, and please use idiot proof style as I am kind of new in this.

Apr 8, 2013
Your current version is too old. Download from here and put the file on your phone. Then select the downloaded package manually from the updater app and install.

Make sure you download the correct package for your phone!