diff --git a/src/Libraries/Mono/System.Globalization.Extensions.dll b/src/Libraries/Mono/System.Globalization.Extensions.dll
new file mode 100644
index 000000000..8c0861579
Binary files /dev/null and b/src/Libraries/Mono/System.Globalization.Extensions.dll differ
diff --git a/src/Libraries/Mono/System.Runtime.InteropServices.RuntimeInformation.dll b/src/Libraries/Mono/System.Runtime.InteropServices.RuntimeInformation.dll
new file mode 100644
index 000000000..e55b5eb23
Binary files /dev/null and b/src/Libraries/Mono/System.Runtime.InteropServices.RuntimeInformation.dll differ
diff --git a/src/Libraries/Mono/System.Text.Encoding.CodePages.dll b/src/Libraries/Mono/System.Text.Encoding.CodePages.dll
new file mode 100644
index 000000000..414770bc0
Binary files /dev/null and b/src/Libraries/Mono/System.Text.Encoding.CodePages.dll differ
diff --git a/src/Libraries/Mono/System.Threading.Overlapped.dll b/src/Libraries/Mono/System.Threading.Overlapped.dll
new file mode 100644
index 000000000..c06475843
Binary files /dev/null and b/src/Libraries/Mono/System.Threading.Overlapped.dll differ
diff --git a/src/Libraries/Mono/readme.txt b/src/Libraries/Mono/readme.txt
new file mode 100644
index 000000000..f1251a98f
--- /dev/null
+++ b/src/Libraries/Mono/readme.txt
@@ -0,0 +1,3 @@
+Copied from mono/4.5/Facades of the mono 5.4 release.
+These are the mono version of the dotnet Core TypeForwardedTo assemblies.
+Using these assemblies is no longer necessary once we reach mono 5.18 as minimum version
\ No newline at end of file
diff --git a/src/MonoFacades.targets b/src/MonoFacades.targets
index 733bd3b6d..6e1cc5484 100644
--- a/src/MonoFacades.targets
+++ b/src/MonoFacades.targets
@@ -7,36 +7,45 @@
Warning: We ONLY support facades that reside directly in MonoFacadesPath, otherwise the joining of items becomes complicated.
Any MonoFacade listed that doesn't exist on disk will be removed instead of replaced.
+
+ See: https://github.com/mono/mono/blob/master/tools/nuget-hash-extractor/download.sh
+ That list defines assemblies that are prohibited from being loaded from the appdir, instead loading from mono GAC.
-->
$(MSBuildThisFileDirectory)Libraries\Mono\
+
+ $(ResolveReferencesDependsOn);
+ SubstituteMonoFacadesBuild
+
+
+
+
+
+
-
-
-
-
-
+
-
-
- %(ResolvedFileToPublish.Identity)
+
+
+
+ %(ReferenceCopyLocalPaths.Identity)
$(MonoFacadesPath)%(Filename)%(Extension)
-
-
-
+
+
+