Can I Update to the new iOS 7 when it comes out?

So i have an iphone 4s. The phone is originally locked with sprint but I got it factory unlocked so I can have any plan i want. I was using simple mobile for at least 2 days but I had no service at all and my Wi-Fi was currently being fixed. So i switched to T-Mobile. Is it safe to update to the new iOS 7 without my iphone losing the lock? I want to know because I'm dying for this update.

As a IOS 7 Beta Tester, if your iPhone is unlocked, as of right now, you will loose your unlock; however, apple may change this as we get closer to the public release of IOS 7.