Raise the minimum requirements for Gecko 1.9.2 (and any versions of  
Firefox built on 1.9.2) for Windows builds to require Windows XP  
Service Pack 3 or higher.

Background:

Supporting multiple OS versions is not zero cost, in terms of testing,  
code complexity and developer sanity.  We have previously raised the  
minimum requirement to Windows 2000 for Firefox 3.  We have also  
raised the minimum requirements for Linux and Mac builds in that same  
timeframe.  While we have not formalized a policy by which we drop  
support for OS versions, in general the main concerns have been how  
recently the OS versions have been available and sold (in some cases)  
as well as the ability and costs involved for users to upgrade.  
Additionally, the continued availability of security updates for the  
OS level is important, as users on unsupported of operating systems,  
especially Windows, are highly vulnerable no matter what we do, so  
there is a strong argument against giving those users a reason to stay  
on that platform.

On July 13, 2010, Microsoft will end all support for Windows 2000 (all  
service packs) and Windows XP Service Pack 2 (XP SP1 and the original  
XP have already passed their end of support).  This means that after  
this date, these OS versions will not get any security updates and  
will not receive any support from Microsoft.  Service Pack 3 is a free  
upgrade for all XP users.  Windows 2000 has no free upgrade path, but  
has not been available at retail since March 2004, and was last  
legally sold as a preloaded OS in March 2005, which is over four years  
ago, and will be more than five years from when we ship the last  
supported version of Firefox.  Users should be able to successfully  
migrate to XP or Linux if they intend to keep using their old hardware.

Affected Users:

All users still running either Windows 2000 or Windows XP Service Pack  
2 (or lower).  As Service Pack 3 is a free upgrade for XP users, only  
Windows 2000 users will be forced to change their OS to use the next  
version of Firefox.

As we intend to ship the next version of Firefox in early 2010,  
Firefox 3.5 will continue to be supported under our current support  
policy (six months after the next version) until after those OS  
versions are no longer supported, so users will continue to be  
supported by Mozilla as least as long as their OS is supported.

Relevant Links:

General Microsoft Support Lifecycle Policy:
http://support.microsoft.com/lifecycle/

Windows Service Pack Support End Dates:
http://support.microsoft.com/gp/lifesupsps#Windows

Windows 2000 Support Lifecycle
http://support.microsoft.com/lifecycle/?p1=3071

Windows Life-Cycle Policy (licensing availability)
http://www.microsoft.com/windows/lifecycle/default.mspx