Upgrade to iOS No. 12.1.1, released last week, may interfere with the transmission of cellular data on the iPhone and thus prevent access to the Network. It is reported by Forbes with reference to the official support forum of Apple. Despite the fact that the problem is most likely not a mass, it can affect iPhone owners all compatible models regardless of the provider that provides their connection.
It seems that the described problem can be observed in all countries without exception, and thus appear quite different. According to some users, after upgrading the connection to LTE is optional and depends on the running applications. So, the smartphone provides the WhatsApp and Google search, but limits the effect of Twitter or Amazon. The connection is not observed at all, and therefore likely not associated with the launch of specific programs.
LTE not working on iPhone. What to do
Apple for its part still has not given any comments on this matter, without providing any effective ways to fix the problem. Therefore, some enthusiasts decided to organize the work of their devices independently. For this, they have updated the carrier settings and performed a hard reset of the devices. Unfortunately, this has not led to any tangible results.
Bugs the beta version of iOS
Apparently, the failure in question stretches from the time of beta testing iOS 12.1.1, which means that Apple could not be aware of it. In any case, how to assure the participants of the program pre-test, they have repeatedly observed the signs described problems on their smartphones, throughout inputfilename. On what hoped in Cupertino, deciding to let the spelling slide, while we can only guess.