diff --git a/source/ExtensibilityTests/ExtensibilityTests.csproj b/source/ExtensibilityTests/ExtensibilityTests.csproj
index aed8465..a431644 100644
--- a/source/ExtensibilityTests/ExtensibilityTests.csproj
+++ b/source/ExtensibilityTests/ExtensibilityTests.csproj
@@ -7,7 +7,7 @@
   <ItemGroup>
     <PackageReference Include="Assent" Version="1.7.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.0.0" />
-    <PackageReference Include="NSubstitute" Version="4.3.0" />
+    <PackageReference Include="NSubstitute" Version="4.4.0" />
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="4.2.1" />
   </ItemGroup>