diff --git a/test/Tk.Extensions.Tests/Tk.Extensions.Tests.csproj b/test/Tk.Extensions.Tests/Tk.Extensions.Tests.csproj
index e488e6e..092809e 100644
--- a/test/Tk.Extensions.Tests/Tk.Extensions.Tests.csproj
+++ b/test/Tk.Extensions.Tests/Tk.Extensions.Tests.csproj
@@ -23,7 +23,7 @@
     <PackageReference Include="Shouldly" Version="4.3.0" />
     <PackageReference Include="FsCheck.Xunit" Version="3.3.3" />
     <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="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.1.5">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>