Have you looked at the Acrobat JS API Reference manual?
The app object has the viewerVersion property that will let you determine the version of Acrobat/Reader the user is using. You can then use the app object's alert method to display a message.
I have no problem determining which version they have. My question was whether in addition to providing them with a popup notice, I could also bring up the Adobe Updater screen.
I would use the response from the alert, asking if they want to upgrade, to optionally open the URL for the Adobe Reader install page.
But no you cannot run the updater, nor (in my opinion) should a PDF have that ability.
The page I am talking about is the page Adobe presents for installing Reader and that page selects the OS and version.
Also many firms will not let end users update supplied programs.
I am not sure why one needs to update to the most recent version. This should only be done if a feature that is only available for a newer version is used by the form.