Mozilla is on track to debut the new "Australis" user interface (UI) for Firefox next month after promoting the UI to its beta build last week.
Australis, the first visual overhaul of Firefox since March 2011, was added to the "Beta" channel of Firefox 29 on March 20. Mozilla uses a three-stage development process that ships Aurora, Beta and Release versions of each version of Firefox, with six weeks separating Aurora and Beta, another six between Beta and Release.
If everything goes as planned, Mozilla will offer Australis to the release version -- the build most users run -- on April 29. But it's possible that the open-source developer will push Australis further into the future.
Australis is Mozilla's attempt to both streamline the browser's UI and standardize it across all platforms, ranging from the desktop -- where versions are available for Windows, OS X and Linux -- to mobile. Mozilla has a version of Firefox for Android, but recently shelved its "Metro" version for Windows 8.1.
Many of Australis' visual changes are subtle, with more rounded tabs, inactive tabs that fade deeper into the background and a revamped customization panel. Australis also dumps the orange-colored Firefox menu in Windows, an element that first popped up in Firefox 4.
Although Mozilla said that "most users are very happy with the new design," citing a survey of those who used Australis on the Aurora channel, it acknowledged criticism as well.
"Of course, as with any interface change, not everyone is happy," the company noted in a March 18 blog about the survey. "With a change this significant, there are some users who didn't like Australis for a variety of reasons."
To assuage critics, Mozilla said it would make some tweaks to the UI. It has also created a visual tour of the UI that users can view when they update Firefox to a version including Australis, and published instructions for downloading and customizing an add-on that transforms Firefox's Australis UI into something approximating the classic design of 2011-2014.
The Beta build of Firefox for Windows, OS X and Linux can be downloaded from Mozilla's website.
If Australis doesn't release with Firefox 29 in April, its next shot will be Firefox 30, which is scheduled to ship June 10.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is firstname.lastname@example.org.