diff --git a/Chapter.14/StockTicker.Server.Cs/packages.config b/Chapter.14/StockTicker.Server.Cs/packages.config
index bd72a49..342c25d 100644
--- a/Chapter.14/StockTicker.Server.Cs/packages.config
+++ b/Chapter.14/StockTicker.Server.Cs/packages.config
@@ -11,7 +11,7 @@
   <package id="Microsoft.AspNet.WebApi.WebHost" version="5.2.3" targetFramework="net47" />
   <package id="Microsoft.CodeDom.Providers.DotNetCompilerPlatform" version="1.0.5" targetFramework="net47" />
   <package id="Microsoft.Net.Compilers" version="2.1.0" targetFramework="net47" developmentDependency="true" />
-  <package id="Microsoft.Owin" version="3.1.0" targetFramework="net47" />
+  <package id="Microsoft.Owin" version="4.0.0" targetFramework="net47" />
   <package id="Microsoft.Owin.Cors" version="3.1.0" targetFramework="net47" />
   <package id="Microsoft.Owin.Host.HttpListener" version="3.1.0" targetFramework="net47" />
   <package id="Microsoft.Owin.Host.SystemWeb" version="3.1.0" targetFramework="net47" />