Apple released iOS 27.0.1 earlier this week after launching iOS 27 in September. The update fixes a Face ID-related restart issue on the iPhone 18 Pro and iPhone 18 Pro Max. However, AT&T is now telling some customers to install the update immediately. The carrier says it is also addressing a serious network issue affecting the iPhone 18 Pro Max.
According to an automated AT&T message, the issue can prevent an iPhone 18 Pro Max from completing calls, texts and data sessions. The message also warns that emergency calls to 911 may be affected.
There is one problem with AT&T’s claim. Early reports from several AT&T users suggest that iOS 27.0.1 does not resolve the network issue. Affected users are still unable to connect to the carrier’s network after the update is installed.
The problem seems to affect calls, texts and mobile data. Users also report seeing “SOS” in the status bar of their iPhone 18 Pro Max. Not all iPhone 18 Pro Max on AT&T appear to be affected. Nevertheless, reports suggest that the issue is widespread among some users on the carrier’s network.
The iPhone 18 Pro doesn’t seem to have the same problem. One possible reason is the different modem hardware used in the two models. The iPhone 18 Pro Max reportedly used a Qualcomm modem. Meanwhile, the iPhone 18 Pro uses Apple’s own C2 modem.
For now, affected AT&T customers will have to wait for another fix. Apple and AT&T do not yet have a clear explanation for the ongoing network problem.