diff --git a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
index 95498ca69c..1cd80fda4e 100644
--- a/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
+++ b/fcs/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.Tests.fsproj
@@ -100,7 +100,7 @@
   
   <ItemGroup>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="nunit.framework">
diff --git a/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj b/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
index 99611113df..f927fc8016 100644
--- a/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
+++ b/fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj
@@ -626,7 +626,7 @@
       <HintPath>$(FSharpSourcesRoot)\..\packages\System.Reflection.Metadata.1.4.2\lib\portable-net45+win8\System.Reflection.Metadata.dll</HintPath>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
     <Reference Include="System.ValueTuple">
       <HintPath>$(FSharpSourcesRoot)\..\packages\System.ValueTuple.4.3.1\lib\netstandard1.0\System.ValueTuple.dll</HintPath>
diff --git a/fcs/nuget/FSharp.Compiler.Service.nuspec b/fcs/nuget/FSharp.Compiler.Service.nuspec
index 5b05dba395..bfb19e2661 100644
--- a/fcs/nuget/FSharp.Compiler.Service.nuspec
+++ b/fcs/nuget/FSharp.Compiler.Service.nuspec
@@ -19,7 +19,7 @@
         <summary>F# compiler services for creating IDE tools, language extensions and for F# embedding.</summary>
         <dependencies>
             <group targetFramework="net45">
-                <dependency id="System.Collections.Immutable" version="1.2.0" />
+                <dependency id="System.Collections.Immutable" version="1.3.1" />
                 <dependency id="System.Reflection.Metadata" version="1.4.2" />
             </group>
         </dependencies>
diff --git a/packages.config b/packages.config
index 57ee60f4b1..8a0d01eaae 100644
--- a/packages.config
+++ b/packages.config
@@ -12,7 +12,7 @@
   <package id="MicroBuild.Core.Sentinel" version="1.0.0" />
 
   <!-- Actual dependencies of FSharp.Compiler.dll and FSharp.Core.dll -->
-  <package id="System.Collections.Immutable" version="1.2.0" />
+  <package id="System.Collections.Immutable" version="1.3.1" />
   <package id="System.Reflection.Metadata" version="1.4.2" />
   <package id="Microsoft.DiaSymReader.PortablePdb" version="1.1.0"  />
   <package id="Microsoft.DiaSymReader" version="1.1.0" />
diff --git a/setup/FSharp.SDK/component-groups/Compiler_Redist.wxs b/setup/FSharp.SDK/component-groups/Compiler_Redist.wxs
index ae8a46aad6..78ed928905 100644
--- a/setup/FSharp.SDK/component-groups/Compiler_Redist.wxs
+++ b/setup/FSharp.SDK/component-groups/Compiler_Redist.wxs
@@ -171,7 +171,7 @@
       </Component>
 
       <Component Id="Compiler_Redist_System.Collections.Immutable.dll" Guid="$(fsharp.guid(Compiler_Redist_System.Collections.Immutable.dll, $(var.LocaleCode)))">
-        <File Id="Compiler_Redist_System.Collections.Immutable.dll" Source="$(var.NugetPackagesDir)\System.Collections.Immutable.1.2.0\lib\netstandard1.0\System.Collections.Immutable.dll" />
+        <File Id="Compiler_Redist_System.Collections.Immutable.dll" Source="$(var.NugetPackagesDir)\System.Collections.Immutable.1.3.1\lib\netstandard1.0\System.Collections.Immutable.dll" />
       </Component>
 
       <Component Id="Compiler_Redist_System.Reflection.Metadata.dll" Guid="$(fsharp.guid(Compiler_Redist_System.Reflection.Metadata.dll, $(var.LocaleCode)))">
diff --git a/setup/packages.config b/setup/packages.config
index b2376a2008..aded14292c 100644
--- a/setup/packages.config
+++ b/setup/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="System.Collections.Immutable" version="1.2.0" />
+  <package id="System.Collections.Immutable" version="1.3.1" />
   <package id="System.Reflection.Metadata" version="1.4.1-beta-24227-04" />
   <package id="Microsoft.DiaSymReader.PortablePdb" version="1.1.0"  />
   <package id="Microsoft.DiaSymReader" version="1.0.8" />
diff --git a/src/FSharpSource.Settings.targets b/src/FSharpSource.Settings.targets
index 718817a879..11a1cd12bd 100644
--- a/src/FSharpSource.Settings.targets
+++ b/src/FSharpSource.Settings.targets
@@ -35,6 +35,7 @@
     <RoslynVersion>2.3.0-beta2-61719-01</RoslynVersion>
     <RoslynVSBinariesVersion>15.0</RoslynVSBinariesVersion>
     <RoslynVSPackagesVersion>15.0.26201</RoslynVSPackagesVersion>
+    <SystemCollectionsImmutableVersion>1.3.1</SystemCollectionsImmutableVersion>
     <VSSDK_BUILDTOOLS_VERSION>Microsoft.VSSDK.BuildTools.15.0.26201</VSSDK_BUILDTOOLS_VERSION>
 
     <MicrosoftVisualStudioThreadingVersion>15.3.23</MicrosoftVisualStudioThreadingVersion>
diff --git a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.BuildFromSource.fsproj b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.BuildFromSource.fsproj
index 75b2fac99e..29ee129406 100644
--- a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.BuildFromSource.fsproj
+++ b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.BuildFromSource.fsproj
@@ -607,30 +607,9 @@
   </ItemGroup>
   <Import Project = "$(MSBuildThisFileDirectory)../../FSharpSource.BuildFromSource.targets" />
 
-<!--
-    "System.Collections.Immutable":"1.2.0",
-    "System.Diagnostics.Process": "4.3.0",
-    "System.Diagnostics.TraceSource": "4.3.0",
-    "System.Linq.Expressions": "4.3.0",
-    "System.Linq.Queryable": "4.3.0",
-    "System.Net.Requests": "4.3.0",
-    "System.Reflection.Emit": "4.3.0",
-    "System.Reflection.Metadata": "1.4.2",
-    "System.Reflection.TypeExtensions": "4.3.0",
-    "System.Runtime": "4.3.0",
-    "System.Runtime.InteropServices": "4.3.0",
-    "System.Runtime.Loader": "4.3.0",
-    "System.Security.Cryptography.Algorithms": "4.3.0",
-    "System.Threading.Tasks.Parallel": "4.3.0",
-    "System.Threading.Thread": "4.3.0",
-    "System.Threading.ThreadPool": "4.3.0",
-    "Microsoft.DiaSymReader.PortablePdb": "1.1.0",
-    "Microsoft.DiaSymReader": "1.1.0",
-    "System.ValueTuple": "4.3.1"
--->
   <ItemGroup>
     <ProjectReference Include="$(MSBuildThisFileDirectory)..\FSharp.Core\FSharp.Core.BuildFromSource.fsproj" />
-    <PackageReference Include="System.Collections.Immutable" Version="1.2.0"></PackageReference>
+    <PackageReference Include="System.Collections.Immutable" Version="$(SystemCollectionsImmutableVersion)"></PackageReference>
     <PackageReference Include="System.Diagnostics.Process" Version="4.3.0"></PackageReference>
     <PackageReference Include="System.Diagnostics.TraceSource" Version="4.3.0"></PackageReference>
     <PackageReference Include="System.Linq.Expressions" Version="4.3.0"></PackageReference>
diff --git a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
index 10e0f26c59..acfb28e533 100644
--- a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
+++ b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj
@@ -663,7 +663,7 @@
       <HintPath>..\..\..\packages\System.Reflection.Metadata.1.4.2\lib\portable-net45+win8\System.Reflection.Metadata.dll</HintPath>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>..\..\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>..\..\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
     <Reference Include="System.ValueTuple">
       <HintPath>..\..\..\packages\System.ValueTuple.4.3.1\lib\netstandard1.0\System.ValueTuple.dll</HintPath>
diff --git a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.netcore.nuspec b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.netcore.nuspec
index 8dfb2b6c25..302e10bbe2 100644
--- a/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.netcore.nuspec
+++ b/src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.netcore.nuspec
@@ -16,7 +16,7 @@
         <dependencies>
             <group>
                 <dependency id="NETStandard.Library" version="1.6.0" />
-                <dependency id="System.Collections.Immutable" version="1.2.0" />
+                <dependency id="System.Collections.Immutable" version="1.3.1" />
                 <dependency id="System.Diagnostics.Process" version="4.1.0" />
                 <dependency id="System.Diagnostics.TraceSource" version="4.0.0" />
                 <dependency id="System.Linq.Expressions" version="4.1.0" />
diff --git a/src/fsharp/FSharp.Compiler.Private/project.json b/src/fsharp/FSharp.Compiler.Private/project.json
index c50e8438f9..bee86e2f41 100644
--- a/src/fsharp/FSharp.Compiler.Private/project.json
+++ b/src/fsharp/FSharp.Compiler.Private/project.json
@@ -1,7 +1,7 @@
 {
   "dependencies": {
     "NETStandard.Library": "1.6.1",
-    "System.Collections.Immutable":"1.2.0",
+    "System.Collections.Immutable":"1.3.1",
     "System.Diagnostics.Process": "4.3.0",
     "System.Diagnostics.TraceSource": "4.3.0",
     "System.Linq.Expressions": "4.3.0",
diff --git a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec
index f75b32320c..bf3b7397d7 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec
+++ b/src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec
@@ -17,7 +17,7 @@
             <group targetFramework=".NETStandard1.6">
                 <dependency id="Microsoft.NETCore.Platforms" version="1.0.1" />
                 <dependency id="NETStandard.Library" version="1.6.0" />
-                <dependency id="System.Collections.Immutable" version="1.2.0" />
+                <dependency id="System.Collections.Immutable" version="1.3.1" />
                 <dependency id="System.Console" version="4.0.0" />
                 <dependency id="System.Diagnostics.Process" version="4.1.0" />
                 <dependency id="System.Diagnostics.TraceSource" version="4.0.0" />
diff --git a/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.nuspec b/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.nuspec
index ff32c71716..ac1069ee47 100644
--- a/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.nuspec
+++ b/src/fsharp/FSharp.Compiler.nuget/Testing.FSharp.Compiler.nuspec
@@ -16,7 +16,7 @@
             <group targetFramework=".NETStandard1.6">
                 <dependency id="Microsoft.NETCore.Platforms" version="1.0.1" />
                 <dependency id="NETStandard.Library" version="1.6.0" />
-                <dependency id="System.Collections.Immutable" version="1.2.0" />
+                <dependency id="System.Collections.Immutable" version="1.3.1" />
                 <dependency id="System.Console" version="4.0.0" />
                 <dependency id="System.Diagnostics.Process" version="4.1.0" />
                 <dependency id="System.Diagnostics.TraceSource" version="4.0.0" />
diff --git a/src/fsharp/Fsc-proto/Fsc-proto.fsproj b/src/fsharp/Fsc-proto/Fsc-proto.fsproj
index 7b554d80c8..fb99ce70c2 100644
--- a/src/fsharp/Fsc-proto/Fsc-proto.fsproj
+++ b/src/fsharp/Fsc-proto/Fsc-proto.fsproj
@@ -465,7 +465,7 @@
       <HintPath>$(FSharpSourcesRoot)\..\packages\System.Reflection.Metadata.1.4.2\lib\portable-net45+win8\System.Reflection.Metadata.dll</HintPath>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
     <Reference Include="System.ValueTuple">
       <HintPath>$(FSharpSourcesRoot)\..\packages\System.ValueTuple.4.3.1\lib\netstandard1.0\System.ValueTuple.dll</HintPath>
diff --git a/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj b/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj
index 97218f9922..6cc7e0ada8 100644
--- a/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj
+++ b/vsintegration/Vsix/VisualFSharpFull/VisualFSharpFull.csproj
@@ -325,10 +325,8 @@
       <SpecificVersion>False</SpecificVersion>
       <HintPath>$(FSharpSourcesRoot)\..\packages\Newtonsoft.Json.10.0.2\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
-    <!-- Microsoft.CodeAnalysis.Features requires 1.2.1 but the rest of F# uses 1.2.0 -->
-    <!-- If we don't get the version right here the wrong version is copied during the build  -->
-    <Reference Include="System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+    <Reference Include="System.Collections.Immutable">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
   </ItemGroup>
   <Import Project="$(FSharpSourcesRoot)\..\vsintegration\src\FSharp.tools.targets" />
diff --git a/vsintegration/Vsix/VisualFSharpOpenSource/VisualFSharpOpenSource.csproj b/vsintegration/Vsix/VisualFSharpOpenSource/VisualFSharpOpenSource.csproj
index de084fad4f..f59abe67aa 100644
--- a/vsintegration/Vsix/VisualFSharpOpenSource/VisualFSharpOpenSource.csproj
+++ b/vsintegration/Vsix/VisualFSharpOpenSource/VisualFSharpOpenSource.csproj
@@ -324,10 +324,8 @@
       <SpecificVersion>False</SpecificVersion>
       <HintPath>$(FSharpSourcesRoot)\..\packages\Newtonsoft.Json.10.0.2\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
-    <!-- Microsoft.CodeAnalysis.Features requires 1.2.1 but the rest of F# uses 1.2.0 -->
-    <!-- If we don't get the version right here the wrong version is copied during the build  -->
-    <Reference Include="System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+    <Reference Include="System.Collections.Immutable">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
   </ItemGroup>
   <Import Project="$(FSharpSourcesRoot)\..\vsintegration\src\FSharp.tools.targets" />
diff --git a/vsintegration/src/FSharp.Editor/FSharp.Editor.fsproj b/vsintegration/src/FSharp.Editor/FSharp.Editor.fsproj
index a6403bcfaa..bde8237c08 100644
--- a/vsintegration/src/FSharp.Editor/FSharp.Editor.fsproj
+++ b/vsintegration/src/FSharp.Editor/FSharp.Editor.fsproj
@@ -268,7 +268,7 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="Newtonsoft.Json">
diff --git a/vsintegration/src/FSharp.LanguageService.Base/FSharp.LanguageService.Base.csproj b/vsintegration/src/FSharp.LanguageService.Base/FSharp.LanguageService.Base.csproj
index 3c08e86fe1..f8121a8f34 100644
--- a/vsintegration/src/FSharp.LanguageService.Base/FSharp.LanguageService.Base.csproj
+++ b/vsintegration/src/FSharp.LanguageService.Base/FSharp.LanguageService.Base.csproj
@@ -178,7 +178,7 @@
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualStudio.ComponentModelHost.15.0.26201-alpha\lib\net46\Microsoft.VisualStudio.ComponentModelHost.dll</HintPath>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Core\FSharp.Core.fsproj">
diff --git a/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj b/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj
index 28e76eebe5..96ed9e9404 100644
--- a/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj
+++ b/vsintegration/src/FSharp.LanguageService/FSharp.LanguageService.fsproj
@@ -239,7 +239,7 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
       <Private>True</Private>
     </Reference>
   </ItemGroup>
diff --git a/vsintegration/src/FSharp.ProjectSystem.FSharp/ProjectSystem.fsproj b/vsintegration/src/FSharp.ProjectSystem.FSharp/ProjectSystem.fsproj
index df3461eb7b..9a63914dc4 100644
--- a/vsintegration/src/FSharp.ProjectSystem.FSharp/ProjectSystem.fsproj
+++ b/vsintegration/src/FSharp.ProjectSystem.FSharp/ProjectSystem.fsproj
@@ -211,10 +211,8 @@
     <Reference Include="Microsoft.VisualStudio.Shell.$(RoslynVSBinariesVersion), Version=$(RoslynVSBinariesVersion).0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
       <HintPath>$(FSharpSourcesRoot)\..\packages\Microsoft.VisualStudio.Shell.$(RoslynVSBinariesVersion).$(RoslynVSPackagesVersion)\lib\Microsoft.VisualStudio.Shell.$(RoslynVSBinariesVersion).dll</HintPath>
     </Reference>
-    <!-- Microsoft.CodeAnalysis.Features requires 1.2.1 but the rest of F# uses 1.2.0 -->
-    <!-- If we don't get the version right here the wrong version is copied during the build  -->
-    <Reference Include="System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+    <Reference Include="System.Collections.Immutable">
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Compiler.Private\FSharp.Compiler.Private.fsproj">
       <Project>{2E4D67B4-522D-4CF7-97E4-BA940F0B18F3}</Project>
diff --git a/vsintegration/tests/unittests/VisualFSharp.Unittests.dll.config b/vsintegration/tests/unittests/VisualFSharp.Unittests.dll.config
index e4a42b8fd0..060a3b86e0 100644
--- a/vsintegration/tests/unittests/VisualFSharp.Unittests.dll.config
+++ b/vsintegration/tests/unittests/VisualFSharp.Unittests.dll.config
@@ -47,10 +47,9 @@
         <assemblyIdentity name="Microsoft.VisualStudio.Platform.VSEditor.Interop" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
         <bindingRedirect oldVersion="14.0.0.0-15.0.0.0" newVersion="15.0.0.0" />
       </dependentAssembly>
-      <!-- Microsoft.CodeAnalysis.Features requires 1.2.1 but the rest of F# uses 1.2.0 -->
       <dependentAssembly>
         <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
-        <bindingRedirect oldVersion="1.0.0.0-1.2.1.0" newVersion="1.2.0.0" />
+        <bindingRedirect oldVersion="1.0.0.0-1.3.1.0" newVersion="1.3.1.0" />
       </dependentAssembly>
     </assemblyBinding>
   </runtime>
diff --git a/vsintegration/tests/unittests/VisualFSharp.Unittests.fsproj b/vsintegration/tests/unittests/VisualFSharp.Unittests.fsproj
index 007ec01e1c..5603dd8058 100644
--- a/vsintegration/tests/unittests/VisualFSharp.Unittests.fsproj
+++ b/vsintegration/tests/unittests/VisualFSharp.Unittests.fsproj
@@ -336,7 +336,7 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Collections.Immutable">
-      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.1.2.0\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+      <HintPath>$(FSharpSourcesRoot)\..\packages\System.Collections.Immutable.$(SystemCollectionsImmutableVersion)\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <ProjectReference Include="$(FSharpSourcesRoot)\fsharp\FSharp.Core\FSharp.Core.fsproj">