diff --git a/test/win.Dockerfile b/test/win.Dockerfile
index 4c3525e..a675343 100644
--- a/test/win.Dockerfile
+++ b/test/win.Dockerfile
@@ -1,3 +1,3 @@
-FROM mcr.microsoft.com/windows/nanoserver:1809
+FROM mcr.microsoft.com/windows/nanoserver:2009-KB4579311
 COPY hello.txt C:
 CMD ["cmd", "/C", "type C:\\hello.txt"]