I learned longv ago that using the same profile for two different versions is, potentially, disastrous.
I have four Firefox versions on my XP computer. Except for Firefox 5 portable, which comes with a different configuration, 3.6.18, 5.0.1 and 6 b1 are used with different profiles.
But it is interesting to see this in the Firefox Portable page:
For the confused, the 5.0.1 release of Firefox is to fix some issues on the Mac version of Firefox. No changes are made on the Windows side other than updating the version number (so it is not being pushed via Firefox's built-in updater... which will only add to the confusion). In the portable release, we've also fixed a bug some users were experiencing on Windows XP when run as admin with specific plugins/extensions.
I had decided to update 5.0 regular, just for the heck of it, and I had to go outside Mozilla to get the update.
And, I will update the portable, but it could be necessary. But, that's an entirely different story.
My point with Antony, was that he was not forced into an update, a fact that he abhors, but he has not taken advantage of the fact that Mozilla gives you a way to opt out. The Options|Advanced|Update come, by default, with a check mark for the program, addons and search engines. I, generally, uncheck the Firefox check, and, as a second check, I select that I am asked what to do. It is amazing that these options were available from day 1, and so many people are surprised when an update has been downloaded.
I am using Firefox 5 portable, and nothing happened, but I will get the update. As for 3.6.19, I don't care.
UserAgent: Mozilla/5.0 (Windows NT 5.1; rv:5.0) Gecko/20100101 Firefox/5.0