I have a Windows service written in C# using VS2005.
The installation is via a wizard that calls msiexec to install the msi file also created using VS2005.
I am
There are several things that need to be done to get "upgrades" to work with MSI's if you want to automatically remove the previous version.
First some background information about the mysterious "codes". There are 3 codes (GUID's) associated with an MSI:
The Upgrade Code should never change. For you upgrade scenerio, the Product Code must be changed for each version. Additionally, as you mentioned, you must bump the version number. The Product Code and Upgrade Code can be found by selecting your setup project and going to the Properties Window. The Package Code is hidden in Studio and will always be updated.
The item you are probably missing, is that you also need to set the RemovePreviousVersions setting in the Properties Window to true.
An easier way to manage this is to REMOVE the AssemblyFileVersion from all assemblies, including the main executable and all the managed DLLs.
In each of your AssemblyInfo.cs files, I recommend doing something like this if you don't care about the version numbers, but want to have some traceability.
[assembly: AssemblyVersion("1.1.*")]
// don't need this [assembly: AssemblyFileVersion("1.0.0.0")]
Everything still compiles fine, and if you don't have the AssemblyFileVersion defined, then the installer assumes that everything is different every time (which is probably fine if you are installing all of the DLLs next to the main EXE).
I spent a long time figuring this out, especially if I don't want to have to increment anything manually!
One more thing in addition to mohlsen's answer (For Visual Studio 2008):
In order for your Primary Output (your EXE!) to upgrade properly, you must increment the FILE VERSION
This setting can be found in the Project Properties: Application Tab -> Assembly Information