Hi. I'm getting a family member of mine to get a factory unlocked iphone 5 from the UK online store and then ship it to me. (Apple hasn't released the iphone in my country yet). I was reading the info provided on the UK online store and it said that it will run on any 'supported' GSM carrier in the world. What does that mean? Will it not activate if I put any active sim in it? I'm in Pakistan btw using Warid Telecom if it helps.