The phone is a Sony Xperia Z1 Compact running Android 5.1.1. I have been able to successfully use the app on this device to view programmes but have never successfully accessed the device registration function. I have had to try to access the device registration function when the app fails to connect me to a Sky programme because it indicates that access on the mobile phone is not enabled, even though access should be allowed for the programme in question. I then have to access the device registration function via my laptop instead, which I can, but usually cannot delete and re-add the phone to correct the problem because of the limitation on the number of times the registration can be changed in a month.
Access to Sky programmes is intermittent at best. Even the function to access the Sky Sports app directly rather than via your app is functionally incompetent as, although the Sky app should permit you to click the VM logo to sign in with the VM Id and Password, when you do so, no keyboard pops up with which to enter them!!!