Mozilla decided to release the final version of Firefox 4 after receiving widely acceptance for its final candidate version Firefox 4 Beta 12, which was released on Feb 26.
"Firefox 4 RC1 has received a very warm welcome; it's time to make a decision to ship. As of now, there are no known issues that would stop us from shipping RC1 as final. At the conclusion of our regular 11:30AM triage session on Wednesday, 16 March, release drivers will decide whether to ship RC1 as Firefox 4," said Mozilla's Damon Sicore.
Various technology blogs reported that Mozilla is planning a new version of Firefox. Firefox 3.5 and 3.6 can upgrade to the new version by selecting 'Check for updates' from the Help menu and the Firefox 4 users will be automatically upgraded to newer version.