diff --git a/src/TestFixture/TestFixture.csproj b/src/TestFixture/TestFixture.csproj
index bb708fa..77460ef 100644
--- a/src/TestFixture/TestFixture.csproj
+++ b/src/TestFixture/TestFixture.csproj
@@ -15,7 +15,7 @@
   </PropertyGroup>  
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'net462' ">
-    <PackageReference Include="System.Collections.Immutable" Version="8.0.0" />
+    <PackageReference Include="System.Collections.Immutable" Version="9.0.2" />
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="8.0.0" />
   </ItemGroup>