AT&T tells iPhone 18 Pro Max users to install iOS 27.0.1 fix

AT&T texted iPhone 18 Pro Max customers on 1 October 2026 telling them to install iOS 27.0.1 immediately, warning that some phones may be unable to complete calls, texts and data, including calls to 911. The automated message directed customers to Settings, then General, then Software Update, and told them to contact AT&T or Apple with questions.9to5mac.com

The message matters because AT&T is for the first time formally acknowledging a cellular problem affecting its iPhone 18 Pro Max customers, a problem users have reported since the phone launched on 18 September 2026. Apple's own release notes for iOS 27.0.1 mention a Face ID fix for iPhone 18 Pro models but say nothing about cellular connectivity, so AT&T's guidance goes beyond what Apple has documented publicly.heise.de

What AT&T's text message said

The text message read: "Hi, it's AT&T. Action needed: An important Apple software update for your iPhone 18 Pro Max is available. Some phones may be unable to complete calls/text/data, including to 911. Update to iOS 27.0.1 immediately — Settings > General > Software Update." AT&T customers with questions were told to contact AT&T or Apple.

Affected users cannot connect to AT&T's network for phone calls, text messages or data, either persistently or intermittently, and their devices typically enter SOS mode as a result. In SOS mode the phone can only send a satellite emergency call. The problem does not affect every iPhone 18 Pro Max, but discussion threads across the Apple Support Community, Reddit and MacRumors Forums indicate thousands of users have experienced it.

Why the modem difference matters

Heise notes that because the X80 also shipped in the iPhone 17 Pro and 17 Pro Max, compatibility problems should not have occurred. The German publication suggests Apple may have introduced software errors during its switch to the C2 modem in other markets, errors that appear only on the now less-commonly-used Qualcomm baseband. The underlying cause has not been confirmed, and Apple has not publicly commented.

Early reports from AT&T users suggest iOS 27.0.1 does not fix the connectivity problems. Many affected users say they updated when the software was released and still face the same issues. In an alleged internal email shared on Reddit, AT&T clarified that its guidance about updating to iOS 27.0.1 is meant to help mitigate future impacts, though it is unclear how the update actually helps.

In a statement, an AT&T spokesperson said: "Apple has released a software update to address an issue that may affect calls, data, texts, and 911 calls on a small number of Apple iPhone 18 Pro Max phones." The spokesperson added that AT&T's top priority is ensuring customers can stay connected, and that the carrier is working with Apple to make it right.

What users report after updating

AT&T said iPhone 18 Pro Max users who have experienced or continue to experience issues can return to an Apple or AT&T store for additional support. The alleged internal email added that customers can visit a store for a replacement device, but some customers said their request for a replacement under warranty was declined. Apple's standard U.S. return policy is 14 days.

If a software issue is identified, another update such as iOS 27.0.2 may be required. If the problem turns out to be hardware, Apple sometimes launches a free repair programme. Apple has yet to publicly comment on the matter, and the underlying cause remains unconfirmed. Heise reports no similar mobile-radio problems with the iPhone 18 Pro or 18 Pro Max have emerged from other regions.