Back in 2015, Apple released its own battery case to compete with other companies like Mophie. It is currently only available for the iPhone 6, 6S, and the iPhone 7.
Apple’s current battery case costs $99 and has an 1877 mAh battery inside of it. It has a controversial design that many people found strange and unappealing.
A newer, updated version of the case has not been announced yet for devices like the iPhone 8, iPhone X, iPhone XR, or any of the newer phones. This may change in the future with a new icon being found in the newest watchOS beta (5.1.2 beta 2). The icon was found within the battery widget displaying the charging status for the battery case.
The icon of the new case looks mostly similar to the old case except that the chin at the bottom of the case is much smaller and the camera has been changed to a dual vertical camera to represent devices like the iPhone X and iPhone XS. The chin of the current smart battery case is quite large, so it is good that Apple is making it significantly smaller.
In the past, icons like this one have been found and have turned out to be correct, like with the new iPad not having a home button. This does not mean that Apple will for sure release a new smart battery case, but it is surely a good indication that they are at least considering it.