diff --git a/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj b/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
index b656ebe186..0452b7d5db 100644
--- a/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
+++ b/src/Umbraco.Web.UI/Umbraco.Web.UI.csproj
@@ -206,8 +206,8 @@
     <Reference Include="System">
       <Name>System</Name>
     </Reference>
-    <Reference Include="System.Collections.Immutable, Version=1.2.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\System.Collections.Immutable.1.3.1\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+    <Reference Include="System.Collections.Immutable, Version=1.1.36.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\packages\System.Collections.Immutable.1.1.36\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
     </Reference>
     <Reference Include="System.ComponentModel.DataAnnotations" />
     <Reference Include="System.configuration" />
@@ -239,8 +239,8 @@
       <SpecificVersion>False</SpecificVersion>
       <Private>False</Private>
     </Reference>
-    <Reference Include="System.Reflection.Metadata, Version=1.4.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\System.Reflection.Metadata.1.4.2\lib\portable-net45+win8\System.Reflection.Metadata.dll</HintPath>
+    <Reference Include="System.Reflection.Metadata, Version=1.0.21.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\packages\System.Reflection.Metadata.1.0.21\lib\portable-net45+win8\System.Reflection.Metadata.dll</HintPath>
     </Reference>
     <Reference Include="System.Runtime.Serialization" />
     <Reference Include="System.ServiceModel" />
diff --git a/src/Umbraco.Web.UI/packages.config b/src/Umbraco.Web.UI/packages.config
index 910d4d82d4..555740eda3 100644
--- a/src/Umbraco.Web.UI/packages.config
+++ b/src/Umbraco.Web.UI/packages.config
@@ -35,7 +35,7 @@
   <package id="Owin" version="1.0" targetFramework="net45" />
   <package id="SharpZipLib" version="0.86.0" targetFramework="net45" />
   <package id="SqlServerCE" version="4.0.0.1" targetFramework="net45" />
-  <package id="System.Collections.Immutable" version="1.3.1" targetFramework="net45" />
-  <package id="System.Reflection.Metadata" version="1.4.2" targetFramework="net45" />
+  <package id="System.Collections.Immutable" version="1.1.36" targetFramework="net45" />
+  <package id="System.Reflection.Metadata" version="1.0.21" targetFramework="net45" />
   <package id="Umbraco.ModelsBuilder" version="3.0.7" targetFramework="net45" />
 </packages>
\ No newline at end of file