'Find My Friends' app is invisible on my iPhone 5S, iOS8

Hello, there.

I made my Apple ID in U.S. when I was in university, and at that time I registered my friends who used iPhone series to 'Find my friends' app.

And now I'm in South Korea for graduate school. I bought iPhone 5S last year and updated to iOS8.

At the update, I completely erase every data in my phone and installed iOS8, because I wanted to make my phone looked as new.

And today, I suddenly remembered I can see where my friends are through 'Find my Friends' app.

So I downloaded that app and boom, app wasn't appear on my iPhone.

Funny thing is that in Appstore, the icon shows 'Open' button, so when I touch it, I can open the app.

But the App doesn't appear on the screen, so I cannot run that app in normal way.

Why does it happen on my iPhone?

Is this situation is correct?

Other people's iPhones with iOS8 also hide 'Find my Friends' app and just can access through Appstore?

Well, if my situation happens only to me, my guess is this.

In S.Korea, there is a law that only companies that have location data centre in Korea can provide gps service legally.

So in S.Korea Appstore, there is no Find my Friends app in Appstore.

But as I said, I'm using U.S. store account, so downloadable or not doesn't matter.

So my friends cannot see me because Apple cannot tracks users in Korea.

(FYI, because of this, Korean users cannot use Find my iPhone service. They only can make ringing sound to notify it's there or lock their phone through that app. Poor Koreans..)

With those info, my conclusion is that Apple doesn't allow 'Find my Friends' app exists on Korean iPhone...

In other words, Apple did something to Korean iPhone model to hide 'Find my Friends' service because anyway they cannot provide the location in Korea.

What do you think?

Again, am I only one who cannot see Find my Friends app on the phone?

Or it's normal because my phone is for Korea ..?

Thank you.