For a couple of days I've been getting a popup saying it wanted to upgrade so I let it and each time it quickly popped up another message saying I was already up to date. Hmmm. Today it did it again and this time it went through the whole process but when it was done and I went in to check it the old version was still there. As a last resort I manually forced an update and this time it actually updated to W501. Whew!