I am very disappointed in the app. After trying for weeks with support, thinking it was my Mio device, I tried a different (not affiliated or recommended app that supports Bluetooth heartbeat monitors) and my device works! It is the app that needs to be rebuilt from the ground up. Users wanting to keep you device, just know you can sync your device with any app that supports Bluetooth, not just the apps that Mio say are supported.
Not lovin the update about Mio GO