Mozilla is planning to retire Firefox 3.6 from support, but won't put the 18-month-old browser out to pasture until August at the earliest.

The retirement of Firefox 3.6 would follow that of Firefox 3.5 and Firefox 4.

Firefox 3.5, which Mozilla launched in mid-2009, received its last security update in April. Since then, users have been encouraged to upgrade to either Firefox 3.6 or 4. Going forward, the estimated 12 million users of Firefox 3.5 will see their browser automatically updated to Firefox 3.6, a move the company discussed last month.

This week, Mozilla retired Firefox 4, which debuted three just months ago, as it rolled out Firefox 5.

That move has been criticized by some enterprise IT managers. They've argued that the quick retirement combined with Mozilla's rapid-release scheme -- which delivers a new edition every six weeks -- puts them in an impossible position: By the time they test one version, another will already be out.

Full story: Computerworld