iOS 12.1.2 already had a cellular problem. Now the latest update seems to have the same problem - even worse.
There were already iOS 12.1.2 problems with the mobile phone or data connection. In some cases, those affected were unable to connect to the Internet. However, the error was not detected in all users. Shortly after the release of iOS 12.1.3, reports from Canada and the USA of a limited mobile phone connection appeared. Now reports of general connection problems under iOS 12.1.3 are increasing worldwide. In addition to limited mobile phone connections, Wi-Fi connectivity is also said to suffer. Some users surf with slower Internet, while others have to live with frequent complete outages. Incoming calls are often not allowed through but are redirected directly to the mailbox - the quality of calls is also said to be poorer. However, there are users who have not yet been able to detect any of these bugs.
cause of the error and solution
The cause of the error is still completely unclear. To solve the problem, restarting the device is recommended. In some cases, the network settings may even have to be reset. Both solutions only provide temporary relief. The problem may occur again. Apple has not yet released a statement.