I would also like to second this request.
Also I dont think 4 days is enough of a warning. It should give you one notice when your less than 10 days from your addon expiring, and then not give you another notice that its about to expire until you are less than 5 days. when you are less than 5 days from having it expire the addon should only give you a notice the first time you log in each day. Once the 5 days are up the addon should just deactivate it self and stop loading. At that point in time there would be no more warnings or messages that it needs to be updated.
Really the way I see it we are just renting the services that you are providing, and as such it is our responsiblity to download the updates when they are availible, in exchange you agree to support the current and future versions of your addon and give careful consideration to any ideas for improvents that are given by members of the Carbonite Community.