How to know if my iPhone 4s is factory unlocked?

I Have the iPhone 4s and i currently am using T-Mobile as my plan. My sister gave me the phone and she said the phone was locked and originally from sprint. Which is true. I want to know if it is factory unlocked. I Want to update to the iOS 7 beta 5 because i Don't want to wait for the release. And i'm scared that if I update it the unlock will take off and my phone will not work with my sim card. I Don't have another sim card near me because literally everybody in my house has T-Mobile and everybody else I Know. Is there any other way that I Can find out?

If its unlocked any micro sim from any provider will work in it. Updating the software will not restore or create a network lock.

FYI, it's not safe to install iOS 7 unless you register your device's UDID with a developer account through a site like http://www.udid.in/.It's $5, and then you don't need to worry about Apple disabling your device for trying to install unreleased software.

I don't understand. Are you using the Sprint iPhone on tMobile? If so, it is unlocked.

Register your UDID at www.udidregistration101.webs.com and they can help you get your proper IOS 7 download links and as well help you get IOS 7 onto your iDevice. They will register you within 10 min.

I'm the developer under this account.

Don't upgrade to Beta 5 unless you're registered because it will brick your device. You know if any SIM can work.

  • Will an unlocked iphone 4S work for tmobile if it isn't factory unlocked? I want to get an iPhone 4S and my friend has the iPhone 4 unlocked but i'm worried that if i get it non-factory unlocked it won't work. My uncle tried to do it a couple of months ago and apple said that if it was factory unlocked every time the phone shut off or died it would reset. I was just wondering if the same thing would happen if it wasn't factory unlocked? So if I get it unlocked everytime it will shut off it will reset? That is what i'm worried about.
  • Why factory unlocked iphone 4s is showing that the iphone is not activated? I bought factory unlocked iphone 4s on ebay for my sister-in-law who is in europe. And the seller assured that it is factory unlocked and will work perfectly. I have non activated sprint sim card and when i inserted it in to the iphone it showed that "the iphone is not activated.contact the carrier". What does it mean? Does it mean that the phone is not factory unlocked?
  • Verizon's iphone 5 or factory unlocked iphone 5? Verizon gives iphone 5 at 199$ and the factory unlocked iphone 5 costs 649 $. the verizon's iphone is already unlocked too. so, why should anyone by an iphone for 649$ when its available for much cheaper rate as 199$?
  • Verizon's iphone 5 or factory unlocked iphone 5? - 1 Verizon gives iphone 5 at 199$ and the factory unlocked iphone 5 costs 649 $. the verizon's iphone is already unlocked too. so, why should anyone by an iphone for 649$ when its available for much cheaper rate as 199$? i'm from india, so if i could buy one of these and bring back to india, would i be able to use it in one our networks? So what if i put in a new sim card or use it out of the country?