diff --git a/dir.props b/dir.props
index 78cc11d2a17b..8de0de0aed29 100644
--- a/dir.props
+++ b/dir.props
@@ -157,6 +157,7 @@
   <!-- Set some shortcuts for more terse conditions in project files -->
   <PropertyGroup>
     <TargetsNetCoreApp Condition="$(TargetGroup.StartsWith('netcoreapp'))">true</TargetsNetCoreApp>
+    <TargetsUap Condition="$(TargetGroup.StartsWith('uap'))">true</TargetsUap>
     <TargetsNetFx Condition="$(TargetGroup.StartsWith('net4')) OR '$(TargetGroup)' == 'netfx'">true</TargetsNetFx>
   </PropertyGroup>
 
diff --git a/src/System.Numerics.Vectors/pkg/System.Numerics.Vectors.pkgproj b/src/System.Numerics.Vectors/pkg/System.Numerics.Vectors.pkgproj
index 1d607dbf60e7..7226c74df4c8 100644
--- a/src/System.Numerics.Vectors/pkg/System.Numerics.Vectors.pkgproj
+++ b/src/System.Numerics.Vectors/pkg/System.Numerics.Vectors.pkgproj
@@ -6,11 +6,11 @@
     <MinClientVersion>2.8.6</MinClientVersion>
   </PropertyGroup>
   <ItemGroup>
+    <HarvestIncludePaths Include="ref\netstandard1.0;ref\netstandard2.0">
+      <SupportedFramework>netcore45;wp8;wpa81;netcoreapp1.0;$(AllXamarinFrameworks)</SupportedFramework>
+    </HarvestIncludePaths>
     <ProjectReference Include="..\ref\System.Numerics.Vectors.csproj">
-      <SupportedFramework>net45;netcore45;wp8;wpa81;netcoreapp1.0;$(AllXamarinFrameworks)</SupportedFramework>
-      <!-- Make sure this doesn't get stripped during harvesting.
-           We have an implementation that will work on desktop, thus needs a unique assembly version -->
-      <Preserve>true</Preserve>
+      <SupportedFramework>net45</SupportedFramework>
     </ProjectReference>
     <ProjectReference Include="..\src\System.Numerics.Vectors.csproj" />
   </ItemGroup>
@@ -21,7 +21,7 @@
     <InboxOnTargetFramework Include="xamarinmac20" />
     <InboxOnTargetFramework Include="xamarintvos10" />
     <InboxOnTargetFramework Include="xamarinwatchos10" />
-    <InboxOnTargetFramework Include="netcoreapp2.1" />
+    <InboxOnTargetFramework Include="netcoreapp2.0" />
     <InboxOnTargetFramework Include="uap10.0.16299" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
diff --git a/src/System.Numerics.Vectors/ref/Configurations.props b/src/System.Numerics.Vectors/ref/Configurations.props
index 322defb70701..ed7d2db187fa 100644
--- a/src/System.Numerics.Vectors/ref/Configurations.props
+++ b/src/System.Numerics.Vectors/ref/Configurations.props
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <PackageConfigurations>
       netstandard1.0;
+      net45;
       netstandard;
       net46;
     </PackageConfigurations>
diff --git a/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.cs b/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.cs
index 9936f6695440..3bf096094750 100644
--- a/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.cs
+++ b/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.cs
@@ -301,7 +301,7 @@ public partial struct Vector<T> : System.IEquatable<System.Numerics.Vector<T>>,
         public Vector(T value) { throw null; }
         public Vector(T[] values) { throw null; }
         public Vector(T[] values, int index) { throw null; }
-#if netcoreapp
+#if HAS_SPAN
         public Vector(Span<T> values) { throw null; }
 #endif
         public static int Count { get { throw null; } }
diff --git a/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.csproj b/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.csproj
index ed07ba967e9e..05beeb02a6aa 100644
--- a/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.csproj
+++ b/src/System.Numerics.Vectors/ref/System.Numerics.Vectors.csproj
@@ -3,11 +3,14 @@
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.props))\dir.props" />
   <PropertyGroup>
     <ProjectGuid>{650277B5-9423-4ACE-BB54-2659995B21C7}</ProjectGuid>
-    <IsTargetingNetFx Condition="'$(TargetGroup)'=='netfx' OR '$(TargetGroup)'=='net46'">true</IsTargetingNetFx>
-    <IsTargetingNetCoreApp Condition="'$(TargetGroup)'=='netcoreapp' OR '$(TargetGroup)'=='uap'">true</IsTargetingNetCoreApp>
-    <IsPartialFacadeAssembly Condition="'$(IsTargetingNetFx)'=='true'">true</IsPartialFacadeAssembly>
-    <DefineConstants Condition="'$(IsTargetingNetCoreApp)'=='true'">$(DefineConstants);netcoreapp</DefineConstants>
+    <IsPartialFacadeAssembly Condition="'$(TargetsNetFx)'=='true' AND '$(TargetGroup)' != 'net45'">true</IsPartialFacadeAssembly>
+    <DefineConstants Condition="'$(TargetsNetCoreApp)'=='true' OR '$(TargetsUap)' == 'true'">$(DefineConstants);HAS_SPAN</DefineConstants>
+    <!-- Must match version supported by frameworks which support 4.1.* inbox.
+         Can be removed when API is added and this assembly is versioned to 4.2.* -->
+    <AssemblyVersion Condition="'$(TargetsNetFx)' != 'true'">4.1.3.0</AssemblyVersion>
   </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'net45-Debug|AnyCPU'" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'net45-Release|AnyCPU'" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'net46-Debug|AnyCPU'" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'net46-Release|AnyCPU'" />
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'netcoreapp-Debug|AnyCPU'" />
@@ -23,14 +26,14 @@
   <ItemGroup>
     <Compile Include="System.Numerics.Vectors.cs" />
   </ItemGroup>
-  <ItemGroup Condition="'$(IsTargetingNetFx)'=='true'">
+  <ItemGroup Condition="'$(TargetsNetFx)'=='true'">
     <Reference Include="mscorlib" />
     <Reference Include="System.Numerics" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetGroup)' == 'netstandard1.0'">
     <Reference Include="System.Runtime" />
   </ItemGroup>
-  <ItemGroup Condition="'$(IsTargetingNetCoreApp)'=='true'">
+  <ItemGroup Condition="'$(TargetsNetCoreApp)'=='true' OR '$(TargetsUap)' == 'true'">
     <ProjectReference Include="..\..\System.Runtime\ref\System.Runtime.csproj" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />