Thanks for the information. There's no network outage reported, and there's good coverage in your area. Please follow the below steps and try again.
1.Tap Phone icon.
2.Tap Key Pad if necessary.
3.Enter ##873283# then tap Call icon.
4.When Starting Service Update appears, tap OK.
5.When Service Update Complete appears, tap OK. The Radio will reset.
When Boost displays in the top left corner, the iPhone update has completed.