This might technically be an iOS question, but since it pertains to PPC Macs and the compatibility between them, I thought to post here. I would really like to upgrade my phone at some point (iPhone 3GS) and I would like to upgrade the the most recent phone that I can but still maintain full compatibility with my PPC Macs. Am I correct in my thinking that it would be an iPhone 4S running iOS 6.1.6? As far as I know iOS 7 isn't fully supported in OS X 10.5.8 or with iTunes 10.6.3 but I would just like some confirmation if at all possible. And if I am correct, is there any way to find and unlocked phone somewhere and downgrade the version of iOS?