If we choose "Create the update from version 1.7.44 to the latest version (1.7.45)" will work in the same way I expect or will it update all previous versions to 1.7.45?
It won't really work like you expect it to work. Customers with older versions will be stranded on the old versions. In short, this isn't a good idea.
I can help you find a solution, but I need more information. What are you trying to accomplish? Are you trying to force users to purchase a new license of your software? Are you trying to reduce the amount of files that you upload to your servers? What's the end-goal?