Mozilla has extended support for the Firefox 1.5.0.x browser until at least mid-May, despite earlier plans to stop issuing patches for the its 17-month-old program yesterday.

The company has promised a patch that will automatically update users to the newer Version 2.0 before it pulls the support plug, but delayed that patch to fix urgent security flaws first.

The company had earlier said that yesterday would be the termination date for Firefox 1.5.x support - meaning it would issue no new security updates after that. But when it released Version 1.5.11 last month, Mozilla hinted that the final security fix would not make that deadline.

This week developers decided to delay that last update, Firefox, because of a higher than expected number of bugs awaiting attention.

Only after appears will Mozilla tackle what it is been calling Major Updates, an automated upgrade from 1.5.0.x to 2.0.0.x.

Initial testing of the upgrade, which will update all Firefox 1.5.0.x users who have the browser's auto-updating tool turned on, has been completed. But Mozilla will wait until after is out before dealing with that upgrade.

"Major Updates will [not] likely be pushed out after [] ships," according Mozilla. "We'll gather to discuss why and how we will get there."

According to the most recent schedule on its website, Mozilla had pegged 15 May as the release date for (and a similar security update that brings the newest version to With the delay announced this week, however, that deadline is at risk. A note on Mozilla's schedule stated, "Will likely be pushed out, at least by a week."

Mozilla has committed to supporting older software for only six months after the release of a major update. The policy affects not only Firefox, but also the Thunderbird email client, which recently shifted to Version 2.0.