A software release is the distribution, whether public or private, of an initial or new and upgraded version of a computer software product. Each time a software program or system is changed, the software engineers and company doing the work decide on how to distribute the program or system, or changes to that program or system. Software patches are one method of distributing the changes, as are downloads and compact discs. The software release life cycle is composed of different stages that describe the stability of a piece of software and the amount of development it requires before final release. Each major version of a product usually goes through a stage when new features are added, or the alpha stage; a stage when it is being actively debugged, or the beta stage; and finally a stage when all important bugs have been removed, or the stable stage. Intermediate stages may also be recognized. The stages may be formally announced and regulated by the project's developers, but sometimes the terms are used informally to describe the state of a product. Conventionally, code names are often used by many companies for versions prior to the release of the product, though the actual product and features are rarely secret.

Pre-alpha

Sometimes a build known as pre-alpha is issued before the release of an alpha or beta. In contrast to alpha and beta versions, the pre-alpha is not feature complete. When it is used, it refers to all activities performed during the software project prior to software testing. These activities can include requirements analysis, software design, software development and unit testing.

In typical Open source development, there are several types of pre-alpha versions. Milestone versions include specific sets of functions and are released as soon as the functionality is complete. Nightly builds are versions that are usually automatically checked out from the revision control system and built, typically over night; these versions allow the testers to test the recently implemented functionality immediately, and find the new bugs.

Alpha

The alpha build of the software is the build delivered to the software testers, that is, persons different from the software engineers, but usually internal to the organization or community that develops the software. In a rush to market, more and more companies are engaging external customers or value-chain partners in their alpha testing phase. This allows more extensive usability testing during the alpha phase.

In the first phase of testing, developers generally test the software using white box techniques. Additional validation is then performed using black box or grey box techniques, by another dedicated testing team, sometimes concurrently. Moving to black box testing inside the organization is known as alpha release.