Firefox 3.6 was the last of the legacy versions before Mozilla embarked on its ‘rapid release’ program in 2011 with Firefox 4. Now, after 2 years continuing support, they have finally decided to put it to rest.
.At the same time Mozilla also disclosed that it will be discontinuing Firefox support for older Windows operating systems, coinciding with the anticipated release of Firefox 13 in June. Those affected will be anyone running XP SP1 and older, including Windows 2000.
XP SP2 and SP3 shall remain unaffected. So, if you are running XP SP1 and wish to continue using Firefox, it is recommended you apply the later service packs – at least SP2.
Organizations and businesses should switch to the Firefox Extended Support Release (ESR), which allows for annual updates. The current stable version of Firefox, available through the ‘release update channel’, is Firefox 11.