Afaik, it should say what confirmed the upgrade but if it says "upgrade confirmed", are you able to select a seat in the premium cabin and has the duplicate tab for the waitlisted flight disappeared from your reservation? If yes, then you're good to go-just print out a copy of your upgraded itinerary along with a copy of your e-receipt showing the upgraded cabin (to get the e-receipt to update, find the link on your reservation page to "add an email" to the recpt and on that page you'll see your current email address. Hit submit, wait a few minutes and then view the new receipt)

If your reservation is showing upgrade confirmed but you can't select an upgraded seat and/or the waitlisted flight still shows on your itinerary, call and have the agent re-sync your reservation