Updating OS in Dubai - FaceTime blocked?

So the Macbook has been prompting me to update the OS to El Capitan.

However, I am in Dubai for the next 6 months and I am afraid that if I update here, I will lose FaceTime and other apps that are blocked here?

Am I being paranoid or am I right?

And if it does get blocked, how do I restore it once I am back home? My apple ID and cards are not registered at the UAE iTunes store if that make a difference.