The Short answer is I can only make an educated guess.
I do know is that you need to have a Billing Adress for the country that you are in if you want to buy items from their iTunes Store.
The educated guess is along these lines. Open the iTunes Store, scroll down to the very bottom of the page. In the bottom RH corner you will see a small, round icon representing your Country's flag.
Click on that and you will see simillar icons representing all countries that have iTunes stores available. There are 121 of them. Click on the icon representing the country that you are in and you will be taken to their iTunes store. It will look different from your Countrys' page. Don't worry if you are in Israel, almost all of the items there are in English. You could be brave and try downloading the Update then.
The billing address requirement shouldn't matter because you are not actually buying anything. I don't know how your non native Apple ID will affect things. When I tried to buy something from the English store once, to see what happened, all they were worried about was my lack of an English billing adress.
If you are in a country that does not have an Apple store available, I didn't notice one for Serbia, North Korea, or Iran, then you may be in trouble. There are less than 200 Countries in the world so you will have better than a 50% chance of being okay
Remember, DON'T DO ANYTHING BEFORE YOU BACKUP.
Have fun :-)