Update Readme.md

Readme.md

@@ -103,6 +103,7 @@ dotnet add package CompareNETObjects
 
 # Limitations
 * Custom Collections with Non-Integer Indexers cannot be compared.
+* Private properties and fields cannot be compared for .NET Core 1.3.  They are allowed to be compared in .NET Core 2.0 and higher.
 * DynamicObject type is not supported but will be implemented in 2020 when the library is versioned to .NET Framework 4.5
 * When ignoring the collection order, the collection matching spec cannot be a field on a child or parent class.  It has to be a property or field of the class.  The property has to be a simple type.
 * ElapsedMilliseconds does not work for .NET Standard builds as there is no StopWatch in those frameworks.