Mozilla will give Firefox 3.6 the coup de grace next month by automatically upgrading users of that 2010 browser to Firefox 12.

The move isn't a first for the open-source developer: A year ago, it gave Firefox 3.5 the same auto-upgrade death blow.

According to Alex Keybl, Firefox's release manager, the automatic upgrade of Firefox 3.6 to Firefox 12 will take place in early May, although a date has not yet been set.

The decision to push Firefox 3.6 users to a newer edition has been under discussion for several weeks. In late March, Keybl brought it up on a Mozilla planning discussion thread, saying that the proposal was needed to keep users safe while they browsed.

Mozilla issued its final security update for Firefox 3.6 on Jan. 31, and officially retired the browser from support last Tuesday, April 24.

Mozilla has given Firefox 3.6 users plenty of warning, telling them several times over the last months that they need to upgrade because of the impending retirement. The newest such message told Firefox 3.6 users that it was their last warning before Mozilla switched on automatic upgrading.