Whether or not it is safe to use iPhone Unlocker Pro on your iPhone depends on which way you look at it. While there have been issues reported from iPhone owners who has used the Unlocker Pro to unlock their iPhone, many find it is an easy fix. This fix allows them to choose whichever carrier they want instead of being stuck with whatever carrier locked the iPhone in the first place. Many others are filing complaints and are not happy with this third party unlocking service, so you might want to really consider whether it is worth it or not for you to take the risk.
Something else that’s important to keep in mind about using iPhone Unlocker Pro, or any other type of third party unlocking service is that unlocking your iPhone may void any warranties Also, the U.S. Library of Congress has ruled that it is now illegal for you to unlock your iPhone if it was bought after January 26th, 2013. According to this ruling, carriers can still legally unlock your device for you, but it’s illegal to go through a third-party unlock vendor such as iPhone Unlocker Pro. If you want to be on the safe side, have a carrier unlock your iPhone for you.
Source Cult of MAC