I am going to back up my old iphone 5 to itunes so that I am ready to restore apps and data to my new iphone 6 when it comes. iPhone 5 is currently running IOS 7. I assume the new phone will come with IOS 8. Do I have to upgrade the old iphone 5 to IOS 8 in order to make the information compatible? Or does iTunes just copy it all and not care what operaring system the new phone is running?