Q: i update 8.4.1 on 5s but calling fuction cannot be working !!!

Howdy Amanindia3,

Thanks for using the Apple Support Communities.

I see from your post that your iPhone is either unable to make or receive phone calls.  To help troubleshoot and resolve this issue, please follow the steps in the link below.

If you can't make or receive calls on your iPhone - Apple Support

Take care.