If you switch your old iPhone to Samsung Galaxy S9 / S9+, you might be troubled with data transferring. With MobileTrans, all the contacts, messages, photos and more can be transferred directly.
http://youtu.be/xZXMpXrKuck
Works with all iPhone Models like:
iPhone X, iPhone 8 / 8 Plus;
iPhone 7 / 7 Plus;
iPhone 6S / 6S Plus;
iPhone 6 / 6 Plus