Firefox 4 will automatically update the browser’s extensions, a Mozilla interface designer said Sunday.

Add-ons, also called “extensions” by Mozilla, will update silently in the background, said Jenny Boriss, a Firefox user experience designer, in a blog post yesterday . Earlier versions of the open-source browser notified users of available add-on updates each time Firefox was launched.

Add-on developers can also revamp their wares to allow updates without a Firefox restart, which is currently required.

Firefox 4 Beta 7, the most recent preview of the browser that’s slated to launch in early 2011, includes an option setting for each add-on that lets users switch auto-updating on or off.

Other improvements to the revised add-on manager include a larger display area — the manager appears in its own tab as opposed to a separate window — and global search that locates already-installed add-ons as well as recommended extensions.

Mozilla may be implementing silent updates for Firefox add-ons, but a similar feature for the browser’s security patches remains up in the air.

In August, Mozilla said that it would take a page from rival Google, and add silent, behind-the-scenes security updating to Firefox 4. A month later, however, the feature was tagged as “at risk.”

Last week, Mozilla posted notes that indicated silent updates were still uncertain. Those notes have since been modified, and no longer include a feature-by-feature status listing.

Firefox 4 Beta 7 can be download for Windows, Mac OS X and Linux from Mozilla’s site.