I'm having the same issue here. Got my Charge 4 yesterday and everything is working except it won't install Spotify. The install button is grayed out and there's a notification that says "To install this app, make sure the Fitbit app on your phone and your Fitbit device have the latest update". I tried to uninstall and install the app, and reboot my Charge but nothing happened. I'm using iPhone 6s and I'm a Spotify Premium user. My phone worked perfectly when I used Alta. Has anyone solved this issue here? Thanks.