Before the next version of Firefox is released to the public it goes through months of testing. During this time several developmental builds are released for beta-testers, extension/plugin developers and anyone else who is brave enough to want to try using the new version. These releases are numbered with either an A for Alpha, B for Beta or RC for Release Candidate. So what is the difference between Alpha, Beta and RC builds? Note: this is a more simplified explanation of the different builds.
- Alpha – these releases include the new features that are planned for this version of Firefox that need to be tested. New features may still be added in the next Alpha build. Testing involves making sure the feature works and seeing how it affects the overall Firefox build. Alpha builds are not going to be the most stable and therefore are not really meant to be used by non-developers/testers. Major bugs and crashes are to be expected in the earlier Alpha releases. Typically there are around 3-5 Alpha releases.
Beta – at this point no more new features are going to be added. Existing new features should be functioning without major issues. There may be some minor functionality or computability issues that still may need to worked out. If a feature is still not working correctly in later Alpha releases it can be yanked so that the build can move on to the next stage. These releases are going to be a lot more stable than Alpha, but still there is the risk for some odd misbehavior and the occasional crash. Normally there are fewer Beta releases than Alpha.
Release Candidate – these are the most stable of the developmental builds. These are typically almost ready for final release builds. They are a bit of a fail-safe, just to make sure there are no surprises when the final release comes out. Typically there are 2 or 3 release candidates and the final release candidate becomes the final release.