If you are still using the fourth version of Mozilla's Firefox web browser you might want to quickly update to the recently launched fifth version of Firefox right about now. Venture Beat reports that Mozilla won't be releasing any more security updates to Firefox 4 now that the next version of the web browser is now available. Part of the reason is that Mozilla decided to accelerate development of the Firefox browser and release major new versions of the software more quickly than in the past. That means older versions are being put out to virtual pasture. Indeed the last update for Firefox 4, 4.0.1, was released on April 28. It fixed a number of security issues.
One of the problems with using Firefox is that the browser doesn't automatically update to the new version. It does alert its users that a new update is available but it's up to the user to make the choice to download and install the latest update. This is in contrast to the approach of Google's Chrome browser which just goes ahead and updates to its latest version without needing any approval or action by the browser's user.
As Venture Beat points out, some people might still be using Firefox 4 because some of its third party add-ons or plug-ins are currently incompatible with the new Firefox 5 software. However, if people wait to update Firefox 4 to the new version they run the risk that hackers might find and exploit holes in the now abandoned software.