diff --git a/code/Tests/Utility-WPF.Services.Tests.csproj b/code/Tests/Utility-WPF.Services.Tests.csproj
index 52c320b..c9f13e3 100644
--- a/code/Tests/Utility-WPF.Services.Tests.csproj
+++ b/code/Tests/Utility-WPF.Services.Tests.csproj
@@ -39,8 +39,9 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="Castle.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=407dd0808d44fbdc, processorArchitecture=MSIL">
-      <HintPath>..\packages\Castle.Core.4.4.0\lib\net45\Castle.Core.dll</HintPath>
+    <Reference Include="Castle.Core, Version=5.0.0.0, Culture=neutral, PublicKeyToken=407dd0808d44fbdc">
+      <HintPath>..\packages\Castle.Core.5.2.1\lib\net462\Castle.Core.dll</HintPath>
+      <Private>True</Private>
     </Reference>
     <Reference Include="Microsoft.VisualStudio.TestPlatform.TestFramework, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
       <HintPath>..\packages\MSTest.TestFramework.2.1.0\lib\net45\Microsoft.VisualStudio.TestPlatform.TestFramework.dll</HintPath>
diff --git a/code/Tests/packages.config b/code/Tests/packages.config
index a924774..d96259f 100644
--- a/code/Tests/packages.config
+++ b/code/Tests/packages.config
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Castle.Core" version="5.1.1" targetFramework="net472" />
+  <package id="Castle.Core" version="5.2.1" targetFramework="net472" />
   <package id="Moq" version="4.18.4" targetFramework="net472" />
   <package id="MSTest.TestAdapter" version="3.1.1" targetFramework="net472" />
   <package id="MSTest.TestFramework" version="3.1.1" targetFramework="net472" />