About.

Available API Set
.NET Standard 1.0 1.1 1.2 1.3 1.4 1.5 1.6 2.0 2.1
.NET Core 1.0 2.0 3.0
.NET Framework 4.5 4.5.1 4.6 4.6.1
Mono 4.6 5.4 6.2
Xamarin.iOS 10.0 10.14 12.12
Xamarin.Android 7.0 8.0 9.3
Unity 2018.1 TBD
Universal Windows Platform 8.0 8.1 10.0 10.0.16299 TBD