Firefox 3.6 is likely to be the last supported version of the open-source browser that will work on PowerPC-based Macs, according to a post made on Thursday by the head of the browser project to Mozilla developement planning group members.
Mike Beltzner, director of the Firefox project, said that Mozilla is currently reviewing the number of PowerPC (PPC) users working on the project, "but the likely outcome is that we will not be supporting PPC [PowerPC] for Firefox 4".
The decision, although not official yet, would see machines such as the G5 —Apple's last PowerPC Mac, from 2005 — unable to upgrade to the most recent version of Firefox.
Beltzner explained to the community that there is a lack of PPC support for key technologies such as Just-in-time (JIT) compilation, otherwise known as dynamic compilation, and out-of-process plug-ins (OOPP). This makes it unlikely that Firefox 4 will be developed for the hardware, he said.
"The reason is that we believe that Firefox should be fast, responsive and secure. We cannot deliver that on PPC anymore since we don't have support for the JIT on PPC, nor do we have support for OOPP. Nobody has come forward to help us with that work... the Mozilla Corporation is unwilling to bear the cost of hiring and supporting people to work solely on that platform."
Typically, milestone updates to the browser have seen the introduction of several new features not found in earlier versions, as well as providing fixes for known security holes. However, Mozilla has in the past continued issuing critical security updates for older versions of its browser. Google's Chrome browser also does not provide support for PowerPC machines.
The most recent version of Apple's browser, Safari 5, will run on PPC Macs running OS X 10.5, but unlike Chrome and Mozilla does not run under Linux, the major alternative operating system for PPC Macs. OS X 10.5, code-named Leopard, is the last version of OS X that runs on PPC Macs; OS X 10.6, code-named Snow Leopard, works only with Intel architecture Apple computers.
Beltzner did add that other developers could work on a version of the browser that doesn't use JIT or OOPP features but that it would likely not be branded as 'Firefox'.
Firefox 4 is the latest iteration of Mozilla's popular web browser and introduces a number of new features such as a significantly redesigned interface that sees the addition of a 'Firefox' button, repositioning of tabs, a 'switch to tab' shortcut and synchronisation options for bookmarks, history and open tabs across multiple devices. It also adds hardware acceleration for some Windows users.
Firefox 4 is currently still in beta phase but is publically available to download from the Mozilla Firefox website.