diff --git a/phirSOFT.SettingsService.Test/phirSOFT.SettingsService.Test.csproj b/phirSOFT.SettingsService.Test/phirSOFT.SettingsService.Test.csproj
index 1a61366..ccf9118 100644
--- a/phirSOFT.SettingsService.Test/phirSOFT.SettingsService.Test.csproj
+++ b/phirSOFT.SettingsService.Test/phirSOFT.SettingsService.Test.csproj
@@ -10,7 +10,7 @@
     <PackageReference Include="NSubstitute" Version="4.2.2" />
     <PackageReference Include="NSubstitute.Analyzers.CSharp" Version="1.0.13" />
     <PackageReference Include="nunit" Version="3.11.0" />
-    <PackageReference Include="NUnit3TestAdapter" Version="3.17.0" />
+    <PackageReference Include="NUnit3TestAdapter" Version="4.0.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.6.0" />
   </ItemGroup>