Is this iPhone locked or unlocked?

I'm selling my iPhone 4S and it used to have a postpaid sim. I transferred the postpaid sim to my new iPhone, and put in a prepaid sim into my 4S. It's from the same network, except that its new sim is prepaid, but it does work. So, does that mean it's unlocked?

No. Locked phones work with SIMs from 1 carrier, which is why a pre & post paid SIM from the same carrier will work fine. Doesn't mean it is unlocked though.

  • Why does my unlocked iPhone 3GS stay locked? I jailbroke it with redsnow, unlocked it with Ultrasnow a million times over and it remains locked. Using baseband version 05.13.04 with 5.1.1 iOS. Calls and text work fine, but no data, no matter what. Use Wi-Fi in my house, but that's all i can use. I've spent a week doing this over and over and nothing seems to work. Tried dozens of videos online, countless blogs and i followed every, single step x amount of times. Using straight talk right now, should I try T-mobile maybe?
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