After weeks of delays associated with the most recent two Firefox 3.5 beta’s, Mozilla is now on track to deliver Firefox 3.5 release candidate (RC) 1 in June.

“We’re setting an aggressive code freeze target of next Wednesday, May 20th  for Firefox 3.5 RC” said Firefox Director Mike Beltzner. This puts “the RC release somewhere in the first week of June.”

Currently, there are still outstanding code blocking bugs stopping Firefox 3.5 from hitting RC status. Provided they are all completed in time, we may even see a final release of Firefox 3.5 sometime in late June or early July.

Firefox 3.5 Beta 4 can be downloaded in the mean time from the Firefox beta website.

Mozilla has released Firefox 3.5 Beta 4 (formerly known as Firefox 3.1) and is available in over 70 languages.

This beta includes a faster TraceMonkey JavaScript engine, enhancements to private browsing, and location aware browsing.

For a full list of changes you can read the release notes.

Existing beta users should have the upload pushed out to them, and new testers can download the latest beta from Mozilla.

Mozilla is looking at dropping support for Windows 2000 and versions of Windows XP without at least SP3 installed in early 2010.

The idea is hardly a surprise, as the extended support period offered by Microsoft for the operating systems is ending on 13th July 2010, and would see the requirements for Gecko 1.9.2 raised – Firefox’s rendering engine.

Firefox 3.5 (aka 3.1) are built using Gecko 1.9.1, so the change will not affect users on current or next version of Firefox.

Full discussion on the issue can be read on the mozilla.dev.planning newsgroup.

Mozilla has delayed Firefox 3.1 Beta 3 for a second time, citing numerous bugs in the browsers new JavaScript engine.

Last Wednesday’s status meeting for 3.1 reveale there are still 18 bugs remaining. The meeting minutes show the extent of the delay. “At this time, we don’t have a good estimate for when we’ll be done”.

After the last delay, Firefox 3.1 Beta 3 was expected to be released Febrary 2nd. A new release date is not yet known.

I’m sure some of you may be frustrated by Firefox 3.1’s new tab behaviour when pressing Ctrl + Tab. No longer does it just browse through the tabs, but instead it switches to the most recently viewed tab (much like Windows Alt + Tab.

Thankfully, you can turn the new Ctrl + Tab behaviour off, and return it old skool. Simply follow the steps below:

• Go to about:config in the URL bar
• Set browser.ctrlTab.mostRecentlyUsed to false
• Set browser.ctrlTab.recentlyUsedLimit to 0
• Restart Firefox

All done! Enjoy the old Ctrl + Tab behaviour.