The UnlockMySIM (UMS) is a physical device, therefore, it needs to be inserted in the phone at all times, with the SIM card of your new carrier.
Your UMS will arrive already configured, with the steps indicated in our tutorial doctorsim.com/ums. We guarantee the initial configuration to work as long as no SIM switch nor iOS update is performed after.
If a phone reset or an iOS update is performed the device will relock, even with the UMS inserted. It is likely for the UMS to be configured with the initial steps, but we can not guarantee it 100%.
The UMS is designed to work with the original IOS, therefore, if your iPhone is jailbroken, it will not work. If this is your case, we recommend you reinstalling the original software.