An update may stop the problem before it starts, but it cannot revive an iPhone that has already lost service. Apple says some affected AT&T iPhone 18 Pro Max devices must be replaced.
Apple confirmed on Oct. 2 that a “small number” of iPhone 18 Pro Max devices on AT&T can lose cellular service, disrupting calls, texts and mobile data. Phones already affected cannot have service restored through a software update, while iOS 27.0.1 and a new AT&T carrier settings update are intended to help prevent additional failures.
Organizations managing these devices face two different responses depending on their status. Apple’s statement to MacRumors says working phones should receive the updates, while devices that have already suffered the confirmed service failure need replacement through Apple or AT&T. The problem comes less than a month after Apple introduced its 2026 product lineup, including the iPhone 18 Pro and Pro Max.
Which iPhone 18 Pro Max devices are affected
Apple says it has observed the confirmed issue only on the iPhone 18 Pro Max using AT&T. No other iPhone models or carriers are known to be affected by the same problem. The Pro Max went on sale Sept. 18 alongside the smaller Pro, with the iPhone 18 Pro lineup introducing Apple’s A20 Pro chip, new camera hardware and iOS 27.
Affected phones may lose cellular connectivity, with users reporting devices entering SOS mode. AT&T said the issue may affect calls, data, texts and 911 calls, creating a potential communications problem for businesses that rely on the devices for employees.
Apple released iOS 27.0.1 on Sept. 28 and began issuing the separate AT&T carrier settings update on Oct. 2. The company says the two updates together are intended to “help prevent this issue from occurring,” rather than restore service to phones that have already failed.
The iOS 27.0.1 update also addresses separate problems involving Face ID restarts, camera artifacts and an unresponsive touchscreen. Those fixes should not be confused with the AT&T service failure, which requires replacement once an affected phone loses service.
Users can install iOS updates through Settings > General > Software Update. Carrier settings normally install automatically, but Apple’s support documentation says users can check manually by opening Settings > General > About. Apple said the AT&T update could take up to 14 days from Oct. 2 to arrive automatically.
What affected iPhone 18 Pro Max owners should do
If an iPhone 18 Pro Max has already lost service because of the confirmed issue, Apple says a software update cannot reactivate it. Affected customers should contact Apple Support or AT&T, or visit an Apple Store or AT&T location for a replacement.
Owners whose phones are still working should make sure they are running iOS 27.0.1 and have received the latest AT&T carrier settings. Devices that remain without cellular service or stay in SOS mode should be escalated for replacement rather than subjected to repeated software troubleshooting.
Businesses that have issued AT&T-connected iPhone 18 Pro Max devices should also plan for temporary communication alternatives while affected employees wait for replacements.
Apple has not disclosed the root cause of the service failures. For now, the guidance is straightforward: update working phones, and replace devices that have already lost service because of the confirmed issue.
Read more: Organizations reconsidering an upgrade after the service issue can also see how the iPhone 18 Pro compares with the iPhone 17 Pro across price, performance, cameras and battery life.