iOS system in 12 version works much better than its predecessor, but despite the general satisfaction of users after the latest system updates, there are still errors in overall working of system. After update of iOS to 12.1.1 version some users complain about a disadvantageous error which doesn't allow them to use data transmission. Day after day more people let Apple know that such a problem does exist and for the first time it appeared just after the latest update of system.
This problem applies to all iPhones, regardless of the version. The scale of the problem varies - some users report that mobile data connection works for them in some applications such as Safari browser, and for some users data transmission doesn't work at all. The only way to figure out the problem until Apple fixes the error is to use Wi-Fi as a replacement for data transmission. Interestingly, Apple knew about this issue before releasing the latest update, as system testers of system in 12.1.1 version informed producers about this problem already in the testing phase.