Here’s how you can continue using your old profile:

1. Go to the location of your old profile. Here are the default locations:
• On Windows 9.x (95, 98, or ME), go to C:\WINDOWS\Application Data\Phoenix\Profiles\yourProfileName\someRandomCharacters.slt\.
• On Windows 2000/XP, go to C:\Documents and Settings\yourUserName\Phoenix\Profiles\yourProfileName\someRandomCharacters.slt\.
2. Select the following files (and others that sound like types of profile data you want to transfer to the new profile):

someRandomNumbers.s and someRandomNumbers.w

I think these are for passwords, since their filenames seem to be obfuscated.

bookmarks.html

These are, obviously, for your bookmarks.

cert8.db

These are probably for certificates, so if you don’t have any custom certificates, or if you don’t even know what they are, you probably won’t need to select this file – though I don’t think it’ll hurt.

cookies.txt

These are obviously for your cookies.

cookperm.txt

The file itself states that it’s for HTTP permissions. It wouldn’t hurt to select this file, too.

downloads.rdf

This isn’t essential, but if you use the Download Manager’s list to keep track of files you&rsuo;ve downloaded in the past, you’ll want to select this file.

formhistory.dat

This is, obviously, for saved form information, and it would behoove of you to select this file as well.

history.dat

This is a database containing your browsing history for the amount of days you selected in Options. You don’t need to select this if you don’t regularly use the History sidebar.

key3.db

I can’t figure out what this is for, but it’s a database file, so it must be important, right? :^)

mimeTypes.rdf

You probably won’t need to select this, but if you’ve heavily customized Firefox’s handling of file types, you may want to.

panels.rdf

Unless you use an extension that enhances the sidebar, you won’t need to select this. I didn’t.

prefs.js

This holds most of your preferences. You’ll want to select this one.

search.rdf

This contains your custom search plugins. It isn’t essential; installing new plugins is easy, but getting rid of them is the hard part. Here’s your chance. :^)

secmod.db

I still can’t figure this out, but select it anyhow. It worked for me.

user.js

This contains the custom preferences you set (not the ones you set using the Options dialog). If you didn’t set any, you wouldn’t have this file anyhow.

3. Move or copy these files to where your new profile is stored. Here are the default locations:
• On Windows 9.x (95, 98, or ME), go to C:\WINDOWS\Application Data\mozilla.org\Firefox\Profiles\yourProfileName\someRandomCharacters.slt\.
• On Windows 2000/XP, go to C:\Documents and Settings\yourUserName\mozilla.org\Firefox\Profiles\yourProfileName\someRandomCharacters.slt\.
4. Go to the location of your old profile, then go to the chrome folder.
5. If you specified custom style rules for webpages (such as Block Ads code), move userContent.css to your new profile’s chrome folder. You probably won’t want to continue using any custom style rules you’ve set for the theme you’ve been using, because there’s a new default theme, and because the majority of themes haven’t been updated for 0.9 yet.

I didn’t find a way to transfer toolbar settings to the new profile, but re-customizing your toolbar shouldn’t be too much of a hassle.

In fact, reinstalling your extensions will be much more of a hassle, since Firefox’s extension format has changed for 0.9. Fortunately, if you install the Show Old Extensions extension, you’ll be able to correctly use your old extensions as usual – you’ll still have to find and re-install them, however.

As for themes, good luck. You’ll have to either use an already-existing theme, wait for your favorite theme to get updated (which may not even happen), or update one for 0.9 use yourself.

But don’t worry; you won’t have to do all this again for 1.0.