My app always runs in compatibility mode on the new iPad Pro Simulator. I've installed the latest Xcode 10.1. I've verified it is linked against the latest iOS 12.1. When I run it on an iPhone XS, it correctly uses Safe area insets. Yet it shows a black status bar and a black stripe at the bottom where the Home indicator is located.
Even when I create a sample app with Xcode 10.1 and run it on the iPad Pro Simulator, it is launched in compatibility mode:
How to make the app use the whole screen?
I was seeing the same issue simply by creating a fresh iOS app using the Single View app or the Master-Detail app templates.
I got it working as expected by doing the following:
I deleted all versions of Xcode installed on my computer. I went to my ~/Library/Developer/Xcode
folder and I deleted the following:
DeveloperPortal*
DerivedData
folderInstalls
folder (which just had some empty folders in it)UserData/IB Support
I deleted the Simulator Devices
folderThen I did a fresh download and install of Xcode 10.1 from the App Store.
After that, a clean build of the test app worked as expected. I don't know which of the above steps was really needed but I got it working.