We have upgraded 8.1.3 at one of my friend iPhone 5 device which made Hotspot stopped working. Please release the fix as soon as possible. iPhone 5, iOS 8.1.3

No one here can 'release' anything. This is a user-to-user technical assistance forum. That means your fellow users, not Apple, are here to assist if possible.

If you want to get a message to Apple, either use the Contact Us link at the bottom of this page or use www.apple.com/feedback to provide feedback to Apple.

If you want technical assistance here, state your issue as well as what troubleshooting steps you've tried.

For troubleshooting HotSpot, use this article first: iOS: Troubleshooting Personal Hotspot - Apple Support

No need to post the same problem in multiple threads.

You aren't talking to Apple here. It is a user-to-user forum so there won't be anyone here that can release a fix. I think there would be tons of threads regarding this issue if there was truly a problem with the 8.1.3 release. You may need to try resetting your friend's iPhone or possibly doing a restore. In your post you are listing that you also have the iPhone 5. Did the problem only happen on your friend's phone? If so then it's probably an issue with the iPhone and not anything that a new iOS version would help.