I am Fiona, and I have a question and hope you can help me. I updated my iPhone 6 to iOS 8.4 yesterday, but I found some apps on my computer cannot recognise my phone when I plug in my device. I mean that I used to transfer data with some desktop-based program instead of iTunes. But now the program didn't recognise my phone because of the new iOS 8.4. So can I downgrade from iOS 8.4 to iOS 8.1?