diff --git a/ClosedXML/ClosedXML.csproj b/ClosedXML/ClosedXML.csproj
index fe9a1dc..0484c4e 100644
--- a/ClosedXML/ClosedXML.csproj
+++ b/ClosedXML/ClosedXML.csproj
@@ -45,6 +45,7 @@
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
     <PackageReference Include="DocumentFormat.OpenXml" Version="2.7.2" />
+    <PackageReference Include="Microsoft.CSharp" Version="4.4.0" />
     <PackageReference Include="System.IO.Packaging" Version="4.4.0" />
   </ItemGroup>
 
diff --git a/ClosedXML_Tests/ClosedXML_Tests.csproj b/ClosedXML_Tests/ClosedXML_Tests.csproj
index b0e2f5b..d9eec23 100644
--- a/ClosedXML_Tests/ClosedXML_Tests.csproj
+++ b/ClosedXML_Tests/ClosedXML_Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>netcoreapp2.0;net40;net461</TargetFrameworks>
+    <TargetFrameworks>netcoreapp2.0;net461</TargetFrameworks>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
@@ -51,6 +51,7 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == 'net461'">
+    <PackageReference Include="Microsoft.CSharp" Version="4.4.0" />
     <PackageReference Include="System.IO.Packaging" Version="4.4.0" />
   </ItemGroup>