Mozilla Firefox 188.8.131.52 and 184.108.40.206 were released on Friday, February 23rd. The update release are mainly security and stability bugfixes for the Firefox 2.0.x and 1.5.x versions of the browser. According to the Firefox 220.127.116.11 release notes new changes also include:
Windows Vista Support: Many enhancements and fixes for Windows Vista are included along with the following caveats.
New Languages: Beta releases for several new languages are now available for testing.
Permissions Bug Fixed: In the German (de) locale on Windows and Linux, resolved a problem with certain files tagged as read-only.
If you are planning on using Firefox with Windows Vista, be sure to read the contents shown when clicking on the "following caveats" link. If I had Vista on my desktop I personally would wait to use Firefox until a few more bugs are shaken out. That's just my opinion, of course.
As should be expected, fewer "new features" arrive with Firefox 18.104.22.168. According to the Firefox 22.214.171.124 release notes Mozilla is not recommending Firefox 1.5. for Vista.