And from user comments on the app:
Initially I was not able to hard reset my shoe despite talking with Nike Support. After the update, my left shoe had a white/rainbow color. It would not reboot even after holding both buttons. After about 10 seconds, the lights would turn off, but the shoe would not blink red and reboot as expected. Randomly, I rebooted the right shoe and for some reason I was then able to reboot the left shoe. So for now I can manually adjust the shoes with the buttons but like everyone here, the app won't connect.
Was having the same pairing issues as others noted but finally got it to work. You need to do a manual reset of both shoes per the instructions. 1. Hold down both buttons until they are red and then release. 2. Hold down one button until the lights come on. Continue holding down button while pressing other button 3 times until both are green. 3. Repeat steps on other shoe. After that the app paired on the first time and immediately applied an update to the shoe software and now they don't work.