Mozilla has released Firefox 10.0.4 for Android and 10.0.4 ESR and 12.0 for desktop users on April 24th, 2012. See the release notes for information on what’s new and what was fixed for the desktop version. Desktop users can update via Help > About Firefox or can manually update at getfirefox.com site. A reminder Firefox 3.6.x is no longer supported.
The next scheduled release will be Firefox 13 on June 5th.