diff --git a/BlogHelper9000.Mcp.Tests/BlogHelper9000.Mcp.Tests.csproj b/BlogHelper9000.Mcp.Tests/BlogHelper9000.Mcp.Tests.csproj
index feb0649..443566d 100644
--- a/BlogHelper9000.Mcp.Tests/BlogHelper9000.Mcp.Tests.csproj
+++ b/BlogHelper9000.Mcp.Tests/BlogHelper9000.Mcp.Tests.csproj
@@ -17,7 +17,7 @@
     <ItemGroup>
         <PackageReference Include="FluentAssertions" Version="8.10.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
-        <PackageReference Include="NSubstitute" Version="5.3.0" />
+        <PackageReference Include="NSubstitute" Version="6.0.0" />
         <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="22.1.1" />
         <PackageReference Include="xunit.v3" Version="3.2.2" />
         <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
diff --git a/BlogHelper9000.TestHelpers/BlogHelper9000.TestHelpers.csproj b/BlogHelper9000.TestHelpers/BlogHelper9000.TestHelpers.csproj
index 448120b..0e5ebee 100644
--- a/BlogHelper9000.TestHelpers/BlogHelper9000.TestHelpers.csproj
+++ b/BlogHelper9000.TestHelpers/BlogHelper9000.TestHelpers.csproj
@@ -10,7 +10,7 @@
 
     <ItemGroup>
         <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.9" />
-        <PackageReference Include="NSubstitute" Version="5.3.0" />
+        <PackageReference Include="NSubstitute" Version="6.0.0" />
         <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="22.1.1" />
     </ItemGroup>
 
diff --git a/BlogHelper9000.Tests/BlogHelper9000.Tests.csproj b/BlogHelper9000.Tests/BlogHelper9000.Tests.csproj
index 1e93727..10b07c9 100644
--- a/BlogHelper9000.Tests/BlogHelper9000.Tests.csproj
+++ b/BlogHelper9000.Tests/BlogHelper9000.Tests.csproj
@@ -27,7 +27,7 @@
         <PackageReference Include="FluentAssertions" Version="8.10.0" />
         <PackageReference Include="Microsoft.Extensions.TimeProvider.Testing" Version="10.7.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
-        <PackageReference Include="NSubstitute" Version="5.3.0"/>
+        <PackageReference Include="NSubstitute" Version="6.0.0"/>
         <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="22.1.1" />
         <PackageReference Include="xunit.v3" Version="3.2.2"/>
         <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
diff --git a/BlogHelper9000.Tui.Tests/BlogHelper9000.Tui.Tests.csproj b/BlogHelper9000.Tui.Tests/BlogHelper9000.Tui.Tests.csproj
index 6bd872f..d4f31a3 100644
--- a/BlogHelper9000.Tui.Tests/BlogHelper9000.Tui.Tests.csproj
+++ b/BlogHelper9000.Tui.Tests/BlogHelper9000.Tui.Tests.csproj
@@ -17,7 +17,7 @@
     <ItemGroup>
         <PackageReference Include="FluentAssertions" Version="8.10.0" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.7.0" />
-        <PackageReference Include="NSubstitute" Version="5.3.0"/>
+        <PackageReference Include="NSubstitute" Version="6.0.0"/>
         <PackageReference Include="System.IO.Abstractions.TestingHelpers" Version="22.1.1" />
         <PackageReference Include="xunit.v3" Version="3.2.2"/>
         <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">