diff --git a/src/bench2.4/bench2.4.csproj b/src/bench2.4/bench2.4.csproj
index 0c1823dd..05c976ff 100644
--- a/src/bench2.4/bench2.4.csproj
+++ b/src/bench2.4/bench2.4.csproj
@@ -7,7 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="BenchmarkDotNet" Version="0.14.0" />
-    <PackageReference Include="sly" Version="3.4.5" />
+    <PackageReference Include="sly" Version="3.4.7" />
     <PackageReference Include="System.Memory" Version="4.5.5" />    
   </ItemGroup>
 
diff --git a/src/sly/sly.csproj b/src/sly/sly.csproj
index 645ccd58..43729cc6 100644
--- a/src/sly/sly.csproj
+++ b/src/sly/sly.csproj
@@ -37,7 +37,7 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Newtonsoft.Json" Version="13.0.2"/>
-    <PackageReference Include="System.Collections.Immutable" Version="8.0.0"/>
+    <PackageReference Include="System.Collections.Immutable" Version="9.0.0"/>
     <PackageReference Include="System.Memory" Version="4.5.5"/>
     <PackageReference Include="System.ValueTuple" Version="4.5.0"/>
   </ItemGroup>