Mac OS X 10.5 Support Plans

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Josh Aas

May 17, 2012, 2:59:27 PM5/17/12
I'd like to propose that we remove support for Mac OS X 10.5 in Firefox 16, which should ship on or near October 2, 2012. To be clear: this is not a decision that has been made, I’m proposing it here in order to get feedback.

First, some facts:

Mac OS X Release Dates) 10.5 was released in October of 2007, 10.6 was released in June of 2009, 10.7 was released in July of 2011. Mac OS X 10.8 will be released during the summer of 2012.

Mac OS X User Breakdown) Mac OS X users make up 5.0% of Firefox 12 (current stable) users as of May 12, 2012. Of those Mac OS X users, 17% are on Mac OS X 10.5, 35% are on Mac OS X 10.6, and 48% are on Mac OS X 10.7.

Trends) Mac OS X 10.5 users have been declining by 1-2% per month (as a share of our total Mac OS X users). This means that when Firefox 16 ships, Mac OS X 10.5 users will likely make up less than 10% of Mac OS X users.

Apple releases new versions of its operating systems relatively quickly and each new version contains significant changes that we must adapt to. This requires resources, and with limited resources this sometimes means we have to make tough decisions about where to invest.

We still have significant integration work to do for Mac OS X 10.7 and we’re getting more for Mac OS X 10.8. Currently we have to go back and make sure we didn’t cause problems on Mac OS X 10.5 every time we do integration work for newer OS versions. In addition to the core Mac OS X platform layer (Cocoa widgets), subsystems such as plugins and graphics are affected by the Mac OS X 10.5 requirement.

Build, release, and testing infrastructure resources are also consumed by the Mac OS X 10.5 requirement.

There are already some significant ways in which Firefox on Mac OS X 10.5 has fallen behind Firefox on newer versions of Mac OS X. Accelerated compositing, WebGL, and out-of-process plugins are not available on Mac OS X 10.5.

Google has already announced their plans to drop Chrome’s support for Mac OS X 10.5 [1]. Their timeline is similar to what I'm proposing for Firefox.

Finally, Apple has already stopped supporting Mac OS X 10.5, and Adobe will likely stop shipping security updates for Flash on Mac OS X 10.5 soon. While Apple does not officially drop support for older OS versions, they have stopped shipping security updates and updating applications like Safari.


Dave Townsend

May 17, 2012, 4:22:33 PM5/17/12
On 05/17/12 11:59, Josh Aas wrote:
> There are already some significant ways in which Firefox on Mac OS X 10.5 has fallen behind Firefox on newer versions of Mac OS X. Accelerated compositing, WebGL, and out-of-process plugins are not available on Mac OS X 10.5.

WebGL doesn't work on 10.5? That's pretty surprising to me. If we can't
support modern web technologies then we should drop it as an officially
supported platform.

Cameron Kaiser

May 17, 2012, 7:21:29 PM5/17/12
But that's already true for certain chipsets on other Tier-1
platforms. Similarly, on the security front, Apple did recently
release a patch to address Flashback on 10.5, although they have not
released any others.

That said, I'm not opposed to ending support for 10.5 and I am
actually surprised it took this long to come up again, but I'd like
that to happen in 17 so that 10.5 support at least persists in the
next ESR -- not because I would recommend the ESR to 10.5 users, but
because the next stable release of TenFourFox is going to be based on
17ESR, and we are likely to have an additional user burden from those
Intel users who decline to update to 10.6 (we already have a non-
trivial number of Intel 10.4 users, even though we don't officially
support Intel on any version of OS X). At least keeping 17ESR
compatible with 10.5 reduces our code overhead and gives us some time
to get our widget library completely broken out ("tigerstripe") from
widget/cocoa/ for 18+.

Cameron Kaiser

Benoit Jacob

May 17, 2012, 11:36:33 PM5/17/12
to Dave Townsend,
2012/5/17 Dave Townsend <>:
WebGL is blacklisted on 10.5 indeed.

Supporting any kind of hardware acceleration on Mac OSX , especially
in a content-programmable way like WebGL, is always nontrivial due to
severity of bugs in Apple's OpenGL libraries and the glacial pace at
which they are fixed. We go to great lengths to try to work around
them, but in the case of 10.5, we decided to just blacklist it, see
this bug:

See the screenshot this guy took, showing his Terminal window
texture-mapped into a WebGL 3D scene:

Since then, similar bugs have been found in Mac OSX 10.6 and 10.7, but
fortunately, work-arounds have been implemented, allowing us to avoid
blacklisting WebGL on OSX altogether. We had to significantly limit
certain WebGL capabilities on affected Macs though. For reference,
here are the bugs, but they are currently hidden for security (though
fixed in current versions of Firefox --- Im asking to unhide them

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