My Fitbit Versa has been dim for a long time, so recently I decided to figure out if I could change settings, or if I needed a new Fitbit Versa. My initial search turned up a lot of hits basically saying to bring up the Settings app on the Fitbit Versa and change the brightness. When I tried that, I found the selection was disabled – what’s up with that? I then found this thread on the Fitbit community, found my solution 10 comments down on the thread:

My Brightness setting was dimmed out. I found I had “Sleep Mode” on. When I turned off “Sleep Mode” I was able to change the brightness of the Versa screen. I turned on a set schedule for sleep mode brightness that is separate from “Sleep Mode”. By turning on “Sleep Mode”, that means “Sleep Mode” is always ON (and dim) until you turn “Sleep Mode” off. 

That was the ticket!