Thank you for your reply.
I already use the configuration project and the updater with the switch "/justcheck" to check if a new version is available.
I understand from your reply that it is not possible to use the updater tool to only download the new updates (and install them later). You say that you use your application to download the updates but how do you determine the download url in your application? Now, I use the configuration project to provide these details so that the updater tool can handle the download (and install) and differentiate between critical and non-critical updates. I use the critical update indication to install critical updates automatically without user interface. The non-critical updates are handled in another way.
So how do you pass the download url (and critical/non-critial indication) of the available updates to your application? It would be nice to reuse the information that is configured in the configuration project so that this information does not have to be configured multiple times.