When my Fitbit wouldn't sync last night, I re-installed etc. Had to log back in and it encouraged me to switch to Google login - seemed simple enough, so I did. Little did I know I would lose all access to my friends' data. Now it's just little old me with steps on my friends' list. My friends' data is unavailable till they also migrate to Google, and they have till 2025 to do so. There was NO WARNING, and it can't be reversed once you accept the switch. So disappointing. "Stepping with friends" is a core part of the motivation of Fitbit.