diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index c264d33..ea01a28 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -303,7 +303,7 @@
 # endif
 
 /* Provides the IsWindows7SP1OrGreater() function */
-#include <VersionHelpers.h>
+#include <versionhelpers.h>
 
 /* remove some flags on older version Windows during run-time.
    https://msdn.microsoft.com/en-us/library/windows/desktop/ms738596.aspx */