What is the earliest supported MacOS version that the Unity plugins will work on?

Hi. The earliest version of MacOS that Unity supports is 10.13. However, it seems that running a game using Unity Plugins on 10.13 causes DLL loading exceptions whenever you try to access part of the GameKit API. The errors look like this:

Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/GameKitWrapper
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.dylib
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.dylib
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.so
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.bundle
DllNotFoundException: GameKitWrapper assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) Apple.GameKit.DefaultNSErrorHandler+Interop.DefaultNSErrorHandler_Set(Apple.Core.Runtime.NSExceptionCallback)
  at Apple.GameKit.DefaultNSErrorHandler.Init () [0x00001] in ./Library/PackageCache/com.apple.unityplugin.gamekit@e3d4ad5a2c8e/Source/DefaultHandlers.cs:35 

(Filename: ./Library/PackageCache/com.apple.unityplugin.gamekit@e3d4ad5a2c8e/Source/DefaultHandlers.cs Line: 35)

Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/GameKitWrapper
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.dylib
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.dylib
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.so
Fallback handler could not load library /Users/love/Desktop/REDACTED/Contents/Frameworks/MonoEmbedRuntime/osx/libGameKitWrapper.bundle
DllNotFoundException: GameKitWrapper assembly:<unknown assembly> type:<unknown type> member:(null)
  at (wrapper managed-to-native) Apple.GameKit.DefaultNSExceptionHandler+Interop.DefaultNSExceptionHandler_Set(Apple.Core.Runtime.NSExceptionCallback)
  at Apple.GameKit.DefaultNSExceptionHandler.Init () [0x00001] in ./Library/PackageCache/com.apple.unityplugin.gamekit@e3d4ad5a2c8e/Source/DefaultHandlers.cs:14 

These errors do not appear on 10.15 or later, which is why I am assuming it's a problem with this particular version of MacOS. Have not been able to test 10.14 so not sure how it handles there.

So, here is my question - what is the earliest version of MacOS that the Apple Unity plugins support? It's not documented anywhere on the GitHub page.

// Love