diff --git a/Directory.Packages.props b/Directory.Packages.props
index 0f2884e..ad5b2b5 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -9,7 +9,7 @@
   <ItemGroup>
     <PackageVersion Include="Akka" Version="$(AkkaVersion)" />
     <PackageVersion Include="Microsoft.Extensions.Configuration.FileExtensions" Version="3.1.4" />
-    <PackageVersion Include="System.Collections.Immutable" Version="1.7.1" />
+    <PackageVersion Include="System.Collections.Immutable" Version="9.0.4" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == '$(NetStandardLibVersion)'">
     <PackageVersion Include="System.Configuration.ConfigurationManager" Version="4.7.0"/>