Alpha, Beta, RC

Saturday, September 30th, 2006

In the old days (10+ years I guess) software vendors released different versions of their software, exactly as they do today, but with one big difference. Back then versions was known as alpha version and beta versions, but now we're used to the new concept of release candidates.

The "official" (commonly agreed) definitions for the terms are (source):

Alpha

Specifies a version which is not feature complete.

Beta

Specifies  a version which is feature complete but which is not free of defect. There are known problems which is intended to be fixed. (source)

Release Candidate

Specifies a version which is feature complete and is believed to good enough for final release.

I believe that many software vendors do not follow these definitions, instead we see a lot of beta releases which are far from being feature complete. That is one of the reasons for why it has been necessary to invent the concept of the release candidate. It is a relatively new concept and is today used as - what it was back then - a beta.

Update 18th of February, 2007: See also Jeff Atwood's entry about What's In a Version Number, Anyway? at his Coding Horror blog.