I use Unity daily and I was stuck on 4.1. Right before Unite 2013 I noticed 4.2 was already out on the Unity website. Went into unity, no update notification was showing (I do have check for updates marked). I manually checked for update using the help menu, it claimed my 4.1 version was up to date. So I manually downloaded 4.2 from the Unity website.
Now I noticed there is a 4.2.1, which again, unity does not recognize and I am downloading it manually as we speak. Any ideas why this started happening? The updates were showing fine while I was in the extended trial (Oculus Rift extended trial), but as soon as I added a full Unity Pro license the update notification and checking stopped working.