I hate to dig up an old thread, but rather than making a new one I thought it would be better to bring up discussion on this suggestion. Nearly seven years have passed, and it is very expected in 2020 for applications to just automatically update.
I too have a few older macs that don't get used often. It is wonderful that many applications will just auto-update these days. As useful as it is, I wish Alfred were one of them.
As for the update details, a little notice where the current "Update Available" tab is that says "See What's New" would be much nicer than through an installer, in my opinion. Maybe something a little more invasive if there is a breaking change.