Firefox 3.6.10 and Firefox 3.5.13, which Mozilla launched late Wednesday, addressed what Mozilla said was "a single stability issue affecting a limited number of users."
A crash problem surfaced last week after Mozilla released Firefox 3.6.9 and Firefox 3.5.12 to patch 15 vulnerabilities . Users of all three editions, Windows, Mac and Linux, reported repeated crashes during browser startup after they'd updated to Firefox 3.6.9/3.5.12.
Mozilla halted updates while it investigated. The company has since restarted automatic update delivery.
Mozilla also upgraded Firefox 4's beta this week to deal with a stability bug on that preview.
"We've decided to issue a small beta update in order to fix a stability issue on Windows and some rendering and keyboard/mouse focus issues on OSX related to plug-ins," Mike Beltzner, director of Firefox, said in a message posted to the "mozilla.dev.planning" mailing list.
Like the bug in Firefox 3.6.9/3.5.12, the one in Firefox 4 Beta 5 crashed the Windows browser on or shortly after startup. Mozilla's bug- and code change-tracking Bugzilla database offered more information on the crash bug, which quickly climbed to the top of the crash report chart.
Mozilla pushed the quick fix to users as Firefox 4 Beta 6 on Tuesday.
Because Mozilla had to issue the stability patch, the company also designated Beta 7 as the new feature-frozen version, the one that locks in what will be included and drops what won't. Beta 7 is slated to ship later this month.
"What was known as 'Firefox 4 Beta 6' will now be 'Firefox 4 Beta 7,'" said Beltzner. "We're not adding a beta to our cycle, we're just issuing some fixes for stability and usability to the beta audience, and our numbering system requires that we bump the version number."
Mozilla has already ditched a pair of anticipated features from Firefox 4 to make its deadlines: Account Manager, a beefed-up password manager built into the browser to simplify Web site sign-up; and Inspector, a tool aimed at Web designers and developers who want to drill down for more information on each element in an HTML page.
Other major features, including a silent update mechanism meant to mimic Google Chrome's behind-the-scenes Windows patching, may also get the axe, according to notes posted on Mozilla's site earlier this week.
Panorama, a new name for what Mozilla had been calling "Tab Candy," was also labeled as "At risk" for the first time this week.
Largely driven by the work of Aza Raskin, creative lead of Firefox, Panorama lets users collect tabs into sets, graphically displays those sets, and when users open a tab, shows only those tabs within the group. Firefox 4's new Panorama tab manager is now 'at risk,' and may be dropped from the new browser. Tab Candy/Panorama has been promoted by Mozilla and highly touted by reviewers, including Computerworld's Preston Gralla , who called it " one of the best new browser features since tabs were invented."
It would be a blow to Firefox 4 if Panorama does miss the boat.
Users can update to Firefox 3.6.10 by downloading the new edition or by selecting "Check for Updates" from the browser's Help menu. Firefox 3.5 users can obtain the patched 3.5.13 by calling up the integrated update tool.
Firefox 4 Beta 6 can be downloaded for Windows, Mac and Linux from Mozilla's site in 35 different languages. Users already running a preview of Firefox 4 should have already received an update offer.
Mozilla plans to ship Firefox 4 later this year.