Quote - Firefox 2.0 is still in beta. It won't be considered an update until it has been officially released.

It went final on the 24th:

http://www.mozilla.com/en-US/press/mozilla-2006-10-24.html

Quote - That's interesting as I'm running 1.5, but doing a "Check for Updates..." says there are none.  Maybe they don't consider 2.0 'an update'.

Actually you are quite correct, they dont update major versions with the check for updates thing. It didnt work for when they released the 1.5 version either IIRC.