Over the last several weeks my Firefox 4 kept asking me to upgrade to 5 Beta. You have two options available to you, upgrade and ask later. None of the additional information actually exists. It’s annoying, especially when you’re using your browser for a demonstration in front of an audience.
Here’s how to turn it off.
Type ‘about:config’ (without the quotes) in your location bar. Search for ‘beta’. There may be several items that come up. You want ‘app.update.channel’. Double click that and change ‘beta’ to ‘release’.
That’s it. Enjoy!