Just downloaded the finished project for Chapter 8 and installed and ran on my iPhone with iOS 10 beta 6. Worked fine until: I put a breakpoint on the line that prints out the device token and ran again. Now the phone is bricked, stuck on the spinner and nothing I do gets me out of it including trying DFU mode.
Got the phone unbricked. Had to downgrade back to 9.3 from DFU mode. Good news is , it doesn’t seem like I lost any data. Now to go back to iOS 10 beta 7(Why do I hate myself? )