Today Apple has rolled out iOS 12.1.2 update to the users. The update fixes bugs and eSIM issues on the iPhone XS, XS Max, and XR.
eSIM is one of the biggest features they have introduced in iPhone. The update is not very huge as it is just 100MB patch. iOS 12.1.2 also addresses issues that could affect cellular connectivity in Turkey.
To update to iOS 12.1.2, go into Settings > General > Software Update.