Just a note on behavior when clicking the upgrade link in email announcing a new version. This may be the behavior you want.
I have several DNS CNAME records which amount to aliases for my Discourse site. I normally log in using one alias, logged in as admin, and the new version announcement uses another. When I click the email link I get a blank page because I am not logged in at that CNAME. Perhaps there should be a login screen instead. If I open another tab and log in as admin with the CNAME of the upgrade link, then reload the upgrade link page, all is well. It confused me for a while.