After update from MI FIT to Zepp I did not ask for I could not log in, had to restore factory settings and consequently lost all history. Even a band face needed to be downloaded again. Next time will just throw away this junk with the band. Two stars because Huawei Health is even worse. Mi Fit I used earlier is basic which is fine for me. I cannot comprehend why sleep time cannot be viewed on the band (the device, ver. 4). What you pay is what you get.