While it is true that many rumors did not exist about this, it seems that its implementation is finally suspended. This feature that is available on Apple Watch since the latest version of watchOS 5 henceforth it is finally discarded from the iPhone. And it seems that the Cupertino company had planned to integrate this function in the iPhone, but finally the feature was discarded.
The function allows us to talk to other people without the need for coverage and is something that works very well on the Apple Watch but that few people (at least in my environment) are using. Logically it is one more function and it is always better to have it available, but in this case Apple backs down and the technology known as "Radio Service off Network" it is ruled out for the moment.
It seems that the new iPhone 11 will be without this feature
The middle The Information explains how it was the function that used the 900 MHz spectrum so that users could communicate with each other thanks to radio waves. Intel had been working with Apple on this for some time and allowed to send messages no need to be connected to LTE. The problem is that one of the project leaders left his post last April and then Apple signed peace with Qualcomm and this complicated the development field to continue working on it.
Now it is possible for Apple to use LTE Direct, which is the same but with the need to use the coverage for sending messages. In any case, the new iPhone model is just around the corner and it is possible that they are not complicated with this type of technology that we remember already gave some other problem in the Apple Watch last July. We will see the news of this iPhone 11 that is close to being presented but it seems that this function is completely ruled out, at least for now.
