I was following the second answer here in order to avoid "already installed" message for my newer installation packages. So this is the items I've changed. Everything is ok and I'm getting newer versions installed properly.
<Product Id="*" Name="Product Name" Language="1033" Version="1.9.0.0" Manufacturer="ABCD" UpgradeCode="e820aa3a-0288-45d8-a357-41bc065bbed0">
<Package InstallerVersion="200" Compressed="yes" InstallScope="perMachine" />
<MajorUpgrade AllowSameVersionUpgrades="yes" DowngradeErrorMessage="A newer version of [ProductName] is already installed." />
However, compiler gives me the following warning message:
ICE61: This product should remove only older versions of itself. The Maximum version is not less than the current product. (1.9.0.0 1.9.0.0)
I can't just ignore this message. So the question is how to fix this warning?