diff --git a/build.cake b/build.cake
index cec2e80..cde2b4c 100644
--- a/build.cake
+++ b/build.cake
@@ -89,7 +89,7 @@ Task("Build")
 
 const string DOORSTOP_VER_WIN = "3.1.0.0";
 const string DOORSTOP_VER_UNIX = "1.3.0.0";
-const string MONO_VER = "2020.12.23";
+const string MONO_VER = "2020.12.31";
 const string DOORSTOP_DLL = "winhttp.dll";
 Task("DownloadDependencies")
     .Does(() =>