How to run Xcode 11.4 on macOS Mojave 10.14.6

Question

Background on problem:

I have an iPhone 6s that has updated itself to iOS 13.4. Before the iOS update, I could code + run my app on the device from

Answer 1

My Apple TV 4K was running tvOS 13.3 and I upgraded to 13.4 which required that I use this technique to keep working with Xcode 11.3.1.

What is odd is that in the DeviceSupport folder, Xcode 11.3.1 only ships with tvOS up to 13.2. So how did it ever work with a hardware device running 13.3? I guess 13.2 and 13.3 are close enough that 13.2 still works.

13.4 does not work out of the box, so I copied both 13.3 and 13.4 from the Xcode 11.4.1 app into my 11.3.1 app. All is well again.