Hello @asalinase and welcome to the Community. This might be an issue with the Fitbit app, not your iOS version. What version of the Fitbit app do you have. Tap on your profile avatar, then scroll down and tap on Help & Support.
I'm also moving this thread to the iOS forum, a better fit for your question.
Laurie | Maryland
Sense 2, Luxe, Aria 2 | iOS | Mac OS
Take a look at the Fitbit help site for further assistance and information.
Best Answer