diff --git a/setup-win.py b/setup-win.py
index b1d6753..892078d 100644
--- a/setup-win.py
+++ b/setup-win.py
@@ -6,9 +6,9 @@
 from setuptools.extension import Extension
 
 # you need to download https://www.jadaktech.com/documentation/rfid/mercuryapi
-# https://www.jadaktech.com/wp-content/uploads/2018/11/mercuryapi-1.31.2.zip
+# https://www.jadaktech.com/wp-content/uploads/2019/10/mercuryapi-1.31.1.36-2.zip
 # FIXME: make sure the patch matches the mercuryapi version you have
-mercuryapi = "mercuryapi-1.31.2.40/c/src/"
+mercuryapi = "mercuryapi-1.31.1.36/c/src/"
 
 setup(name="mercuryapi", version="0.5.3",
       ext_modules=[Extension("mercury",