Morning GOM.
Quote from the.edmeister, member on the Firefox forum :-
"Mozilla usually doesn't turn on the update from one major version to the next until the next .1 or.2 minor version is released - like with 3.5.1 or 3.5.2. With Firefox 3.6 is was temporarily turned for a few days about a week after Firefox 3.6 was released, you must have missed that "window" is was available.
I think it's a good thing to wait encouraging users to update to the next major version for at least a month or 6 weeks, to give the developers of other applications that install addons into Firefox to have time to fix their software - so that Firefox users aren't inconvenienced any more than necessary or have users blame Mozilla for their crap not working because a 3rd party didn't have enough foresight to keeps tabs on Firefox new version development and the projected release date ."
Maybe you are currently in this limbo window, in which case the way forward seems to be to download FF 3.6, save it and then install over the version you currently have.