diff --git a/Core/BkwdComp/System.Runtime.CompilerServices.CallerXXAttribute.PreNet45.cs b/Core/BkwdComp/System.Runtime.CompilerServices.CallerXXAttribute.PreNet45.cs
new file mode 100644
index 00000000..165dd4f8
--- /dev/null
+++ b/Core/BkwdComp/System.Runtime.CompilerServices.CallerXXAttribute.PreNet45.cs
@@ -0,0 +1,27 @@
+#if (NET20 || NET35 || NET40)
+namespace System.Runtime.CompilerServices
+{
+	/// <summary>
+	/// Allows you to obtain the full path of the source file that contains the caller. This is the file path at the time of compile.
+	/// </summary>
+	/// <seealso cref="System.Attribute"/>
+	[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+	public class CallerFilePathAttribute : Attribute
+	{
+	}
+
+	/// <summary>Allows you to obtain the line number in the source file at which the method is called.</summary>
+	/// <seealso cref="System.Attribute"/>
+	[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+	public class CallerLineNumberAttribute : Attribute
+	{
+	}
+
+	/// <summary>Allows you to obtain the method or property name of the caller to the method.</summary>
+	/// <seealso cref="System.Attribute"/>
+	[AttributeUsage(AttributeTargets.Parameter, AllowMultiple = false, Inherited = false)]
+	public class CallerMemberNameAttribute : Attribute
+	{
+	}
+}
+#endif
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