I have a member on my family plan that that was originally a free subscriber but converted to the family plan, upgrading the same account. Her Spotify app on iOS shows the old side menu bar, not the bottom menu bar. Spotify version is 18.104.22.1685, the latest. When I log out of her account and log in to mine, the bottom menu bar appears just fine. When logging back in to her account, the side bar reappears.