diff --git a/SerialPortRx.Test/SerialPortRx.Test.csproj b/SerialPortRx.Test/SerialPortRx.Test.csproj
index 859402b..06e79c5 100644
--- a/SerialPortRx.Test/SerialPortRx.Test.csproj
+++ b/SerialPortRx.Test/SerialPortRx.Test.csproj
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.3.2" />
+    <PackageReference Include="System.Reactive" Version="4.4.1" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/SerialPortRx/SerialPortRx.csproj b/SerialPortRx/SerialPortRx.csproj
index 802e300..f74e701 100644
--- a/SerialPortRx/SerialPortRx.csproj
+++ b/SerialPortRx/SerialPortRx.csproj
@@ -13,7 +13,7 @@
     <Authors>Chris Pulman</Authors>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.3.2" />
+    <PackageReference Include="System.Reactive" Version="4.4.1" />
     <PackageReference Include="System.IO.Ports" Version="4.7.0" />
   </ItemGroup>