Index: src/Deltares.DSoilModel.Setup/Product.wxs
===================================================================
diff -u -r7 -r37
--- src/Deltares.DSoilModel.Setup/Product.wxs	(.../Product.wxs)	(revision 7)
+++ src/Deltares.DSoilModel.Setup/Product.wxs	(.../Product.wxs)	(revision 37)
@@ -19,7 +19,7 @@
              Keywords="Installer" Description="$(var.ProductName) Installer" Manufacturer="Deltares"
              Comments="$(var.ProductName) is a program developed by Deltares." />
 
-    <MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." AllowSameVersionUpgrades="yes"/>
+    <MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." AllowSameVersionUpgrades="no"/>
     <MediaTemplate EmbedCab="yes" />
 
     <!-- .Net framework 4.0 -->