Firefox 5 has been moved to the Beta channel on May 20, 2011 (3-days after the May 17th code merge). This build as far as features and changes will be very much similar to the final release due out on June 21st. The name ‘Beta’ may cause some confusion to those who are used to Mozilla’s old release system (Alpha, Beta, Release Candidate). This particular build would fall under the Release Candidate category even though it is labeled as Beta. Development of new features is done and for the most part this build is stable. However, there may still be a couple kinks that need to be ironed out before it can be released for public consumption.
For desktop users how have downloaded and ran any of the 12 Beta builds of Firefox 4, you will be promoted to update to Firefox 5 Beta within 24-48 hours. Otherwise, you can manually install Firefox 5 Beta by going to Mozilla Developer’s News site and clicking the link towards the bottom. Mobile users will need to manually get Firefox 5 Beta from the Android Market.