diff --git a/src/Punchclock/Punchclock.csproj b/src/Punchclock/Punchclock.csproj
index 31e028e..0bd9f81 100644
--- a/src/Punchclock/Punchclock.csproj
+++ b/src/Punchclock/Punchclock.csproj
@@ -8,7 +8,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="System.Reactive" Version="4.0.0" />
+    <PackageReference Include="System.Reactive" Version="4.4.1" />
   </ItemGroup>
 
 </Project>