mine is not working on iphone 4s
Do not disturb is not working on my iphone 4s. I have the latest os version
iPhone 4S, iOS 6.1.3
DND only works if the screen is locked. Are you still having trouble when the screen is locked? If so, you'll need to give a lot more information if you want help. Describe exactly what you mean by "not working".
Best of luck.