diff --git a/src/ReactiveMvvm.Tests/ReactiveMvvm.Tests.csproj b/src/ReactiveMvvm.Tests/ReactiveMvvm.Tests.csproj
index ae2c72f..344034c 100644
--- a/src/ReactiveMvvm.Tests/ReactiveMvvm.Tests.csproj
+++ b/src/ReactiveMvvm.Tests/ReactiveMvvm.Tests.csproj
@@ -12,7 +12,7 @@
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     <PackageReference Include="FluentAssertions" Version="6.12.0" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.10.0" />
-    <PackageReference Include="NSubstitute" Version="5.1.0" />
+    <PackageReference Include="NSubstitute" Version="5.3.0" />
     <PackageReference Include="ReactiveUI.Testing" Version="20.2.45" />
     <PackageReference Include="xunit" Version="2.9.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2">