Some websites reported last week that Apple will , most likely on Thursday, July 14.

Although Mozilla moved earlier this year to a rapid-release schedule that precludes most security or crash-fix updates -- those are instead rolled into the next version of the browser -- it has repeatedly said in its developer mailing lists and meetings that it will issue an emergency fix if necessary. Lion's imminent release fits that bill, Blizzard said.

At the same time Mozilla releases Firefox 5.0.1 for the Mac, the company will also update the older Firefox 3.6 to disable downloadable Web fonts when the browser runs on Lion.

But Blizzard warned Firefox 3.6 users running Lion that they may notice another problem. "[They] may also see scrollbar rendering issues," he noted, then urged them to upgrade to Firefox 5.

Mozilla is planning to , perhaps as early as mid-August after it ships a final security update for the 18-month-old browser.