There are several ways to not shown an update after it has been applied.
1. The update changes the version of your product. if the update changes the version of your product, you can publish the update only for the original version of your product.
2. If the update does not change the version of your product, you can use message conditions to ensure that the update is not shown to a user who has already applied the update. Message conditions allow you to put an "if" statement on the update. For example, only show the update if the version of file xyz.dll is less than 4.0.1. Another example, only show the update if the date of file help.chm is less than 09/24/2003. The "if" condition will be true before the update is applied (so the user will see the update). The condition will be false after the update is applied (so the user will NOT see the update).
Conditions would certainly work for you, but it sounds like you could also use version.....
You are correct that the Update Service only use the first two portions of the version (by default). However you can change that behavior.
You can tell the Update Service to use the full version string by setting an installation property. Depending on which installation tool you are using (Express/ Pro/ Developer/ DevStudio), the method is slighly different. In Developer, you are setting the custom version field in the Update Service property sheet. In Professional, you set the value in script. There is more information in the help.
In doing this, the Update Service would start using the full version string to identify your products (4.0.1). It sounds to me like this is more inline with your needs.
But do I have to overwrite the custom version field value each time I change the ProductVersion? Or can I just write something like [ProductVersion] in that field and then never bother about it?
Most customers manually change the value for each update.
However, I believe that customer version property is either setting a MSI property (MSI projects) or a script value for InstallScript projects. In theory, you should be able to automate that by manually setting that value yourself based on the [productversion]. However, I haven't personally tried it.
