Mozilla released beta versions of Firefox 1.0.6, Thunderbird 1.0.6 and Mozilla Suite 1.7.10 to address some API issues in the latest releases. They ask the community for some help to fix some bugs.
Things to look for in these builds:
*Extensions that interact with web content and events - test on a wide variety of content types
*For Thunderbird, please test the Enigmail Extension
*Test extensions that you normally use to make sure that they function properly
Downloads for Windows, Linux and Mac OS X can be found over here