how can I know whether my iphone can be used in another country
I bought a new unlocked iPhone 4s from amazon in USA, and how can I check whether it can be used in another country?
Also, is there a way to make sure it is really unlocked? it works with att sim card but I couldn't find a sim card from a different carrier. Google says we can edit Settings > Cellular > Cellular Data Network if it is unlocked. Is it always true since I couldn't find cellular data network option?
iPhone 4S, iOS 8.3