diff --git a/api/tests/ProposalSystem.Tests/ProposalSystem.Tests.csproj b/api/tests/ProposalSystem.Tests/ProposalSystem.Tests.csproj
index 9057e56..4fde90a 100644
--- a/api/tests/ProposalSystem.Tests/ProposalSystem.Tests.csproj
+++ b/api/tests/ProposalSystem.Tests/ProposalSystem.Tests.csproj
@@ -17,7 +17,7 @@
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-    <PackageReference Include="NSubstitute" Version="5.3.0" />
+    <PackageReference Include="NSubstitute" Version="6.0.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="8.0.29" />
     <PackageReference Include="coverlet.collector" Version="6.0.4">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>