How can update cellular network

Hello, thin211.

Thank you for participating in the Apple Support Communities. It sounds like you may be experiencing the first issue outlined in this article: 

If you see an Update Failed or Apple Pay Not Available alert after iOS update or restart - Apple Support

If you are, follow the guidance outlined in “What to do next” in that article. 

Warmest Regards.

thin21,

Did you follow the instructions for updating by connecting to a computer in "What to do next" in the article? If you did, you need to set it up for repair. Choose your country on this page to find your iPhone repair options: Apple - Find Locations

You can also contact Apple Support for service options in your area: Get Support

Good luck!