I'd recommend all readers (asides from using the programs) to upgrade to these new versions; they have a bunch of new fixes that missed the 0.9 and 0.7 releases.
"Mozilla.org today released upgrades to both Firefox 0.9 (0.9.1) and Thunderbird 0.7 (0.7.1) to fix some minor bugs present in both releases. Both releases correct some flaws in the Extension System that some users may have been experiencing, as well as a new icon set for the navigation toolbar on Windows and Linux in Firefox 0.9.1. All users of both products should get this upgrade. Builds are available for Firefox 0.9.1 and Thunderbird 0.7.1, as well as updated release notes (Fx, Tb) for both."