The Firefox 5 for Mac OS X has a bug which causes browser to crash when user visits any websites that use downloadable fonts.  Mozilla had informed Apple about the problem prior release of Mac OS X 10.7, but the problem was not fixed and 10.7 was released. Mozilla had identified the bug and assured users of an update to fix the bug but they did not provide an exact date when the update would be available. Firefox 5 update is only intended for Mac OS X users and not for Linux or Windows users.

Mac OS X 10.5 Leopard also has a Java flaw. Mozilla expects to apply the fixes to Firefox 5 before release of the Firefox 6 which is scheduled to release on 16 August. The Firefox update 5 is the first out-of-band update besides the regular minor updates that were done between the release of the browsers two predecessors, the Firefox 4 and Firefox 5. Mozilla is considering to moving to use of newer version of font API to solve the problem. Apple upgraded its distribution of Java in OS X 10.5 Leopard which also led to breaking down of Java plug-in of Firefox 5.  The Firefox 5 update will also restore back the Java functionality to the browser.

While Mozilla releases Firefox 5.01, the Firefox 3.5 will also be updated by the company. The company has decided to disable the downloadable web font when the Firefox 3.5 browser runs on Mac OS X. Mozilla has also notified Mac users that they may experience other problems, if they are still using Firefox 3.5. They may face scrollbar rendering issues in Firefox 3.5. They have urged the users to upgrade to Firefox 5. Mozilla has specifically asked the users to stop using Firefox 3.5 because it will be soon retiring its 18 month old browser and will not be providing any security update after August. The security update for Firefox 3.5 that will be provided in the mid August will be the last update for the browser.

Mozilla has decided to use new font APIs versions in its future Mac versions of Firefox to prevent the browser from crashing in Mac OS X. Firefox 6 and Firefox 7 are the two new versions that will be introduced in near future. The Firefox 6  is still a beta version and is expected to be released on August 15 while the Firefox 7 will be available around Sept 27. The first builds of Firefox 7 are also known as Aurora channel.

Mozilla has also announced that company has decided to adopt and follow an accelerated release cycle for its browsers. The company will provide security fixes for its browsers every six weeks. The new features will also be introduced every six weeks. This is the same pattern that is followed by Google for its Chrome browser.