T-Mobile tells subscribers 'don't update to iOS 10'99+
Just a couple of days ago, several iPhone users found their device bricked when trying to install iOS 10. Apple said it had resolved the issue, and told those receiving the error message to try downloading the new iOS build by using iTunes. If that failed, Apple told them to call Apple support.
T-Mobile says that it expects Apple to push out a fix for the problem sometime in the next 48 hours. Until that arrives, there is a workaround. Those iPhone users who installed iOS 10 and have lost connectivity can temporarily solve the problem by powering down the phone, and then powering it back up.
source: T-Mobile, @JohnLegere,