Nightly

Mozilla provides development builds of Firefox in the following channels: Beta, Aurora, and Nightly. As of March 2013, Firefox 20 beta is in the Beta channel, Firefox 21 alpha is in the Aurora channel, and Firefox 22 pre-alpha is in the Nightly channel.

A release is a specific version of the application, and will have a number associated with it such as 20.0 or 20.0.1. A build narrows down that release even more; you can see specific build information in about:buildconfig. Releases that have been under development go "up" a channel about every six weeks, usually released the day after the code is merged. So the channel is like a slot that is filled every 6 weeks with a new version of the software that has been intensively tested.

See also:

• Managing multiple profiles is very useful if you want to run the release version of Firefox and a Nightly, Aurora, or Beta build, easily, at the same time.

• Releases: https://wiki.mozilla.org/Releases (merge dates)
• Releases: https://wiki.mozilla.org/Firefox/Flight_Tracking
• Rapid Release calendar: https://wiki.mozilla.org/RapidRelease/Calendar

• Nightly release page: http://nightly.mozilla.org/
• Nightly first run page: https://www.mozilla.org/en-US/firefox/nightly/firstrun/
• ftp directory for Nightly http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/