Update: T-Mobile says the issues have been resolved. Here’s a support document regarding the situation.

T-Mobile is warning iPhone customers not to update to iOS 10, the latest software version, after several customers have reported ‘connectivity issues’ caused by the update. The issue appears to be affecting iPhone 6, iPhone 6 Plus, and iPhone SE customers, according to the carrier, although it’s possible a wider group of iPhones including the iPhone 6s and iPhone 6s Plus could be as well.

In tweets issued two days after the iOS 10 software update was released, T-Mobile says it is working with Apple on a fix for the problems and expecting a permanent fix in the next day or two.

While the recommendation for T-Mobile iPhone customers on iOS 9 or earlier is to hold off on updating to avoid the problem, the carrier says iPhone customers already affected by the issue can reboot the iPhone to temporarily restore cellular connectivity.

The cellular connectivity issue reported by T-Mobile customers isn’t the first problem we’ve seen so far with iOS 10’s launch. During the first hour or two of the update going live, customers updating over-the-air were finding their devices bricked which requires connecting to a Mac or PC with iTunes to resolve.

Apple said the initial update problems affected very few people and were resolved during the first hour, although it’s difficult to squash concerns people may have about updating anytime something like that happens.