i'm sorry but no, it is not displayed "just once", i have seen this MULTIPLE times now, hence my frustration and message to the forums, if it were just once I would have dismissed it and gone on with my day
an "upgrade" is still marketing is it not? an email that I could easily ignore (hell I probably got an email I promptly ignored) is one thing but this is another
I get when upgrades happen there is a change log that is displayed that shows what has updated, i appreciate that but this is not that, this is a notification advertising a service that will not go away until i actively close it