diff --git a/build/ReactiveUI.props b/build/ReactiveUI.props
index 3baf83f6b5..1208be34b8 100644
--- a/build/ReactiveUI.props
+++ b/build/ReactiveUI.props
@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="reactiveui" Version="9.19.5" />
+    <PackageReference Include="reactiveui" Version="9.0.1" />
   </ItemGroup>
 </Project>
diff --git a/build/Rx.props b/build/Rx.props
index d40849686f..359ce53a92 100644
--- a/build/Rx.props
+++ b/build/Rx.props
@@ -1,5 +1,5 @@
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.1.5" />
+    <PackageReference Include="System.Reactive" Version="4.0.0" />
   </ItemGroup>
 </Project>