We regret, that the color of your F!DECT 500 can currently not be adjusted and gladly want to take care of it. To do this, please use "Give feedback" in the app menu to send the string #appfid 4586573 and the log of the app as well as the support data and screenshots. Does the 500 go on and off via the app, can "color" be changed via the F!Box?