Thunderbird fans (especially those of you who use Vista), get excited! The first release-candidate has been set loose! If you’ve been holding off on trying earlier alphas or betas (or happen to use Microsoft’s latest OS), but still want to be ahead of the curve a little, this release-candidate is for you.
Be aware, however, that compatibility with many extensions will be broken until 2.0’s official release kicks extension developers into gear. There are also portable versions of Thunderbird 2 (RC1 isn’t up yet) for less invasive testing.