I am using Xcode 10.0 and running in 12.1.1(16C50). It was given below error.
iOS 12.1.1 not supported by Xcode 10.0: Could not locate device support files
Please upgrade your Xcode
IDE to 10.1
.
Xcode 10.1 Release Notes can be found at, https://developer.apple.com/documentation/xcode_release_notes/xcode_10_1_release_notes/