On October 2, Apple said a small number of iPhone 18 Pro Max users on AT&T may lose cellular service and be unable to make calls. Apple says updates are intended to help prevent the issue, while devices that have already lost service need hardware replacement.
What the updates are meant to do
Apple said it had released iOS 27.0.1 earlier that week and was issuing a carrier-settings update on October 2. The company says the updates are intended to help prevent the service issue.
Apple said the carrier-settings update would download automatically over the following 14 days. To check for it manually, open Settings > General > About.
If service is already gone, Apple says replacement is needed
Apple says iOS 27.0.1 and the carrier-settings update will not restore service on a device that has already lost it; those phones need hardware replacement. Apple directs affected owners to Apple Support or AT&T, or to an Apple Store or AT&T location.
One owner's SOS experience
In one owner's account, an iPhone 18 Pro Max worked for three days before losing service and entering SOS mode on AT&T. The owner said iOS 27.0.1 did not resolve the problem. Tethered diagnostics at an Apple Store passed, and reinstalling the operating system restored calls for about 5 to 10 minutes before the phone returned to SOS.
